Unfortunately, that impact can be positive ("wow, the room looks so much bigger") or negative ("why is there a big purple stain on the carpet in your bedroom?"). However, if you take your time and pay attention to what you're doing, painting is a fairly easy skill to pick up (it just takes a little practice... and sometimes some trial and error).
I'm hoping that this instructable will help anyone who's new to painting. Whether you want to set yourself up with some good basic gear to tackle your fixer upper, or you just want to get your dorm room or apartment painted. In a pinch, I'd say you can paint an average sized bedroom (without major drywall/plaster issues for a little less than $50US (including paint, primer, sandpaper brushes, and rollers) and the price can shoot up from there.
Step 1: Figure Out What You're Doing.
Why is this so important?
Well, you want to know what kind of paint you have so you can either put the same thing on top of it, or so you use a primer that will let you switch to a different type of paint. This is most often done in going from oil to latex paints. Latex paints are preferred for general wall painting because they can be cleaned up with water and are therefore much easier to work with, but they really don't like sticking to oil paints (at least not without some help from specialty primers).
Once you know what you have on your walls, you can go to the store and talk to the folks there to find out what they recommend for your situation. One thing I would add though is that you shouldn't feel like you need to buy the most expensive paint out there. I usually go for "one coat" store brands. You might need to use more than one coat, but they do tend to go on better than your average paints. More expensive paints do have somewhat better qualities for painting with them and in some situations do last better once painted, but IMO they aren't that much better. If you're painting something that you may want to repaint soon-ish (e.g. dorm room) you might want to seriously consider saving some money there. That's a personal and financial preference though. However, if you can, you should try to buy yourself some good quality brushes, rollers, etc... If you take good care of them they can last you many many years and they really do make a difference in painting. However, a perfectly reasonable alternative is to buy something very cheap and plan on throwing it away after one or two uses (very cheap brushes tend to do things like starting to lose bristles as you paint which is a pain).
Also, depending on how much you plan to paint (e.g. 1 room vs the whole house/apartment), buying the primer in larger quantities (e.g. 5 gallons) can be a good cost savings (this applies to paint too if you're going with one color for the whole house). You probably don't want to tint it if you plan on using it with multiple colors, but I've haven't really seen a major need for it. Tinting can make things a little easier, but I personally like having a lot of primer on hand so I can really make sure I prep my walls as well as possible rather than worrying about running out of primer in a specific tint (so one 5-gallon can of white primer was my choice for painting 5 rooms in my house in various colors and I still have a decent bit left).
As far as paint goes, there are quite a few options, but three of the more common ones are:
Flat - It's your standard issue paint in areas that don't see a lot of moisture or prolonged dampness. However, it does have a tendency to get dirty easier than other alternatives.
Satin - Is my preferred paint for areas that don't see a lot of moisture. Unlike flat paint, satin has a slight (hence satiny) sheen to it and it looks good without looking outright shiny like semi-gloss. This also means it tends to resist dirt and grime better than flat paint.
Semi-Gloss - This is what you should use in your kitchens and baths. It's got a good bit of shine to it and it tends to handle moisture and humidity better than satin or flat so it's easier to keep clean (you can wipe it down as needed). If you have kids, this is also an option in areas that see a lot of hand-to-wall contact like a hallway or a playroom.
Once you know what kind of paint you want and you've settled on a brand, you can go ahead and choose a color. Some people might say that you should pick your color before the brand, but in my experience and given the color selection for even the least expensive paints, you're better off keeping you budget in mind and then working within what you can afford.
I'm not even going to try and suggest how you go about picking a specific color, but if you're very picky about shades and slight differences in colors, don't rely on a the small paint chips you find at the store. Buy a small sample can (or cans if you want to try multiple shades/colors) and paint it onto something fairly large (a piece of canvas or piece of plywood or sheetrock, whatever is convenient for you.. oh and don't forget to prime it too). Then put it in your room and see how it looks at various times of day and see how it looks against your furniture etc... Make sure you really like it before you proceed. This step isn't absolutely crucial, but it's certainly one to consider before you jump in and start painting.
Also keep in mind that the actual colors and their lightness or darkness can significantly impact your mood. Do a little research into how colors affect mood, and consider how you and your other household members feel about the colors you're considering (some people are more affected than others). The last thing you want is to make a space unpleasant to be in by choosing a color that is not conducive to the room's activity (e.g. concentrating in an office, relaxing and resting in a bedroom, etc...).
Step 2: Clear Out Room/area
You really don't want to be tripping over things while you're dealing with paint. Paint isn't particularly hard to work with, but you would be amazed at how easily you can get it places you didn't intend to. Keeping that in mind, you should try to make plans so that the furrier and smaller members of your household are not going to get into mischief while you work.
Step 3: Evaluate the Condition of the Wall(s)
Try to figure out if you have any wallpaper on your walls (sometimes painted over by previous painters), see if there are any damaged areas in the drywall/plaster or trim. This is the point where you really want to poke and prod anything that looks even remotely odd and make sure it's in paintable condition.
Working on my spooky old house, I've had to replace base molding, patch holes in walls & ceilings, scrape off gunk from walls and moldings, and remove wallpaper before painting. Figuring out what you've got to work with will make it easier to plan ahead for what you need to do and you may realize that you can't get it all done in one weekend/day/afternoon.
Step 4: Brushes....
If you're painting with oil based paint, you would want to use a "china bristle" brush (these will mainly have black bristles). If you are doing mostly fine varnish, the softness of the bristles of a horsehair brush would be better (blond bristles). The "heel" is the part that fits to the handle. A good paintbrush will have a well built heel and you can generally feel the difference between cheap brushes and premium ones. All good brushes also have an empty space where the bristles are placed in the heel. This space is made by a wedge and you can see the space if you check between the bristles. The spacing is where the paint reserve is going to go. Do your best to avoid brushes that have a solid heel (in these the bristles are usually glued into the heel with no spacer). Look for the same design features for a brush used for latex paint but the bristles should be polyester (better) or nylon. Handmade brushes, in general, are better and clearly say they are handmade to justify the premium cost. For both oil and latex though you want wooden handles and you want to see that the heel and handle are joined with nails.
When you're done using them they should be washed properly, combed , and wrapped for storage.
When you're looking for roller covers, the best cover for any but very smooth surfaces is lambswool. Hands down with no comparison, nothing else comes close, but you will have to pay for that quality and they may seem rather expensive compared to the other covers available. Composite covers are a very distant second. However, lambswool will hold more paint, leave a nicer finish, and last for many uses (with proper care). You are lucky to get 3-4 uses out of a cheap roller cover.
If you need to paint smooth and ultra-smooth surfaces then you want to use a solid-fill foam roller cover. It doesn't leave bubbles that last so you can get a finish that does not need to be brushed (combed) out to get rid of them. These rollers look almost like inking rollers. You usually find them in small sizes like 3" or 4". The 6" & 9" sizes are harder to find. The smaller sizes mount on a frame that does not have a cage, the 6" & 9" need a good quality frame with a cage (the spinning thing left on most rollers when they don't have a roller cover in place).
Step 5: Some Tool & Material Recommendations.
B) Some tools for hard to reach spots:
A sanding block on a pole - You don't really NEED this, but if you have a lot of sanding to do, it can be a huge help and a major time saver. The alternative is often having to move your ladder around to get to higher spots and it gets tedious. With one of these you can do most rooms from the ground.
A paint roller on a pole - If you're concerned about weight, consider buying a cheap (and light) mop handle instead of a telescoping painter's pole. The thread is usually the same and the mop handle is a lot lighter. I've been using the gray one in the photo for several years now and for any standard height room (say 9' and lower) it reaches everywhere..
A floor scraper - If you're painting on a solid floor (i.e. not carpet) and doing any sort of drywall work, you may find that you need it. If you should happen to be painting new construction where the drywall has just been taped and mudded, you almost certainly WILL need. it.
Oh, and ignore the pipe bender, that's for a different project ;)
C) Fiberglass Drywall Joint Tape & Wall Repair Fabric - Once you try this stuff you will not want to go back to paper tape when you're doing drywall. It really is that much better to work with and it seems to resist cracking better than paper tape does.
D) Lightweight Setting-Type Joint Compound - Ditch the standard joint compound and go with this stuff. It's a little more expensive, but it really does dry fast (very nice if you're trying to get this done on a weekend or other tight schedule) and it's easy to work with. Well... so long as you don't let it setup in your tray.
In case you're wondering what the bag says it also mentions:
"Weighs up to 25% less.
Easy mixing, smooth applying.
Low shrinkage, excellent bonding."
All good things if you're not a professional.
E) Ladders - If you should decide to buy a ladder, find one similar to this one. It has spaces for tools, screws, paint cans AND roller trays (the long slits are meant to hook into the tray). This is a great use for the top step you're not supposed to be on i the first place ;).
F) Here you have some of the standard issue tools you'll have to get familiar with. Oh, except that white one there, don't bother with it. Totally not worth it.
Step 6: Prep the Wall(s)
Protect floor with a drop-cloth, pretty self explanatory. In some of my photos you see no drop cloth, that's a function of having wood floors that need refinishing. If you have a carpet you really want to preserve then make sure you really do a good job of protecting it with the drop cloth and if it's new construction and you have no floor, don't worry about it, you're set.
Deal with wallpaper - Notice that I didn't say remove wallpaper. Some folks may tell you to just take it all down, but in my experience that should be a function of house age and condition of the paper (e.g. how many times it's been painted). In several of the photos with the green and red walls you can see where I did have to pull off a lot of wallpaper, but I left some of it because it was adhered to the plaster better than the plaster was adhered to the lathe. My rule of thumb is to pull down all the paper that feels like it's not really firmly stuck onto the walls. If the paper isn't painted or if you're in a newer house, then you can definitely try to get it all off, but in an older house you may need to be more cautious.
Patch cracks and holes in drywall/plaster, fix moldings, etc - Self explanatory, but it can take forever. The second photo shows how I had to replace one of the moldings that was just torn apart by the previous owners. This is your chance to also make sure you have the smoothest results possible. As much as possible you want to get rid of bumps and other things that may cause problems while you paint.
Things you probably have to do:
Fill in any cracks or small holes with paintable caulking - Once you have the main stuff done, go back around and use caulking to fill in any remaining cracks of small holes that you may have missed. If your walls are in good shape, you might start from here and skip the previous 2 steps.
Lightly sand the walls - You are not trying to sand your walls into perfect smoothness. In fact you're actually trying to make sure they're roughed up enough to make it easier for the primer to hold on. You'll want to use heavy to medium grit sandpaper for this.
Clean up all the dust and wash the walls - You can use a tack cloth for this, or just grab a sponge and bucket and go to work. This is really not fun, but you'll appreciate doing this later. If you don't you're liable to find your paint job does not turn out the way you wanted it to.
Also remember, sometimes you just can't get your walls perfect no matter how hard you try. The third photo in this set shows one bulge that I tried fixing and I couldn't get completely smoothed out without pulling all that plaster off the wall. While that's certainly an option, I didn't think it was worth it. Ultimately, one thing you do need to accept when doing home improvements is that you can reach a point of diminishing returns and you may have to accept that something is "good enough" or at least "good enough for now given my time and budget constraints"
Step 7: Prime the Walls
In my house, one nice thing about using white primer is that it matches the trim so little mistakes are effectively invisible. It also made it easier to fix some of the moldings that had been painted by the previous owners.
See the next steps for how to cut-in and paint. You usually don't need to be quite as worried about the primer as you do about the paint so you may be able to get away doing the priming without too much cutting in, but you may also need to treat the primer exactly like the paint (for instance if you have stained wood molding). You'll have to evaluate the situation with your walls and the trim (e.g. crown molding, window and door trim etc....) and see what makes sense. Don't hesitate to use multiple coats if you're trying to cover up very vibrant or dark colors.
Step 8: Cutting in (corners & Edges)
Unfortunately it's going to look kinda crappy because you're only doing the cutting in along the edges and corners. If you really want to, you can paint the walls and then do the cutting in, but you run the risk of having the lines be more pronounced. Cutting in and then rolling the paint on with a paint roller seems to work better at minimizing lines. If you can, you also want to paint fairly soon after cutting in, don't let it sit there for days or weeks (I've seen it happen).
There are tons of options for how to cut in at your edges (e.g. trim and molding) and most of the commercial ones kinda suck. I know, I tried them. Your best bet is to learn how to cut in by hand. Unless you're going through the DTs, most people can paint a straight line against something like a molding with a bit of practice. If you don't have a molding then you can carefully draw a straight pencil line where you want to stop painting. It will give you something to guide yourself by just like a molding would. However, remember, you want to go right up to whatever you're using as a guide, you don't want to go onto it or over it, when in doubt stop before you get to it, relax and try again. It's a lot easier to add a little paint than it is to remove a little paint.
If you want to take out some insurance then tape along the edges of your trim or the line you drew, but do NOT think this gives you a license to slap paint up against the tape. It's surprisingly hard to get tape to stick to a molding or wall perfectly and ANY space or gap where it didn't quite stick correctly will let paint seep under if you lay it on too thick. What you really want the tape there for is to block the occasional inadvertent light brush stroke that goes onto what you're trying not to paint. Even with tape though, you should basically be cutting-in freehand. Always use painter's tape, do NOT use masking tape as it has a tendency of not sticking when you want it to and sticking really well when you don't and it can become very hard to remove cleanly after a few days)
If you do it freehand and you make the effort to do it neatly you may end up with tiny imperfections that you can actually just ignore. You'd be surprised at how many mistakes disappear once you're more than 6" from the wall and you're not staring at it intently. Don't be afraid to cut in, take the tape down (if necessary), and walk away for 10-15 minutes. Come back and see if any of the little mistakes you made show up at all. A lot of them probably won't and if some really do stand out, you can fix those.
Step 9: The Fun Part, Finally
Some things to remember.
A) Don't overload your paint brush or roller. It shouldn't be a race from the can to the wall while you hope it doesn't dribble over everything. Experiment a little and get a feel for what the paint is going to do. The once coat paints especially tend to be a bit thick so they're somewhat less prone to drips if you're careful (by the same token if you overload your brush or roller they can drop a lot of paint very quickly).
B) Try to get as much painted at one stretch as possible. Do your best not to drag out the actual painting process for too long. At the very least, paint entire walls at one time.
C) If you are going to use multiple gallons of paint, mix them together and paint from that combined paint. Generally paint is mixed accurately, but you don't want to get caught with a subtle color difference after you've painted the walls.
D) Roll the paint on in a W, N, or M pattern. Don't do this -> l l l l l that's a lot more likely to show lines.
E) As much as possible don't carry the whole gallon (or 5 gallons) of paint around with you. Aside from being heavy and tiring you out, you're a lot more likely to spill them that way. A 1/2 gallon jug of milk with the top cut off makes a great container (complete with handle) for painting. A roller pan is much easier to work with than a whole 5 gallon bucket. If you decide to work with the 5 gallon bucket, consider using a paint strainer that fits inside it. This will help you manage the paint on the roller more effectively than if you just dunk it in the paint.
F) If you're using latex paint, keep a fairly damp cloth with you at all times. This will make it a lot easier to clean up the inevitable drips. Rinse it out and re-wet as necessary.
G) Trash bags make good liners for roller pans. You peel them off and you're done, one less thing to clean.
Step 10: Clean Up
Latex paint is easy to clean up. Just rinse your brushes and rollers with water until the water runs clear, let them dry and store them in a zip-top bag so they don't end up dusty and grimy the next time you want to paint. Make sure they're completely dry though, you don't want to seal in moisture with them.
If you went the cheap route, chuck the brushes and rollers in the bag you used as a liner for the roller pan and you're done.
For cleaning up oil based paints, follow the manufacturer's recommendation and be sure to do it in well ventilated areas (oil based paints and cleaning fluids tend to be volatile and pretty foul smelling).
If you have any paint leftover, use a rubber mallet to seal the can again and (carefully) flip it upside down and put it somewhere out of the way. Storing it upside down is a great way to avoid having your paint dry out even if it's years before you need it again (just be really sure you sealed it right ;)
Finally put you stuff back in the room and enjoy.