I used to get haircuts once every month or so for around $20 a pop, which can really add up over the course of one's life. One day I finally drew the line, bought a buzzer and started cutting my own hair and, after a little practice, my friends' hair too.
Here's a video with the condensed info. Read on for the full details.
Step 1: Assemble Your Materials
Find a nice stool or chair for your subject to sit on. Choose one that is easy to clean (made of vinyl or wood - not fabric) because it's going to get lots of hair on it.
Get a buzzer. Buzzer's from Wahl and Conair are really cheap if you look for them online. I got a buzzer with all the fixings from Amazon.com for $25.
Find something slick to make a gown out of. We used a piece of kite material because it was so slippery that the hair just slid right off.
Step 2: Put a Gown on the Subject
Tape the gown onto the subject. Remember to get it close to their neck so all the little cut off hairs don't fall down their shirt. Those things drive me crazy!
Step 3: Start Buzzing at the Top
Start the buzz by selecting a blade guard size. The number 7 guard is usually the longest, and even that isn't that long - maybe 1" or so. I usually choose about a 6 on the top and a 5 or 4 on the sides. Anything less then a 4 shows the skin underneath, and that's not really an effect I like to do unless it's really hot and I am trying to cool off.
Turn on the buzzer and slowly move from the front of the persons' head to the back. Be careful not to move to quickly as you'll catch their hair in the buzzer and give them a nasty tug.
Make consecutive passes from one side of their head to the other until you've got the whole top cut nice and short.
Step 4: Move on to the Sides and Bottom
Once the top is done you can change the blade guard as necessary and move on to the sides and back of the head. You want to buzz into the grain of the hair so as to catch as much of the long hair in the teeth of buzzer as possible.
Smooth even passes are the key here. It's much better to make a good pass once, rather then repeat the same pass over the same patch of hair over and over.
Step 5: Make a Line Around the Bottom of the Neck
Take the blade guard off and make a nice clean line around the bottom of the persons neck. While you are back there, it's good to take the buzzer and pull down from the line you just created to below the neck line of their shirt to take off all of the fuzzy neck hair.
Some people put a "V" at the bottom center of the neck line, but I don't see why you would want this. I just make one nice smooth continuous line all the way across.
Remember to trim any other extraneous hair as well at this point as the buzzing section of the haircut is coming to an end. Depending on how long they like their sideburns you can use the blade guard and the buzzer to clean those up too and make a nice transition between the sideburns and any facial hair they might have.
Step 6: Grab Some Scissors and Clean Up Around the Ears
Once you're all done with the buzzer you can grab some scissors and carefully trim the hair around your subject's ears. Be careful not to cut them, as that will probably anger them and jeopardize your chances of getting any return business.
That being said, once people realize that they don't have to pay for haircuts, they will most likely come back to you next time they need one. You'll be like Edward Scissor Hands in no time!
Step 7: Shake/Blow Off the Extra Hair
Compressed air works well to blow away any of the little itchy bits that are left behind. Showers work well to wash off the extra hair, and so does baby powder.
Hopefully if you haven't cut your subject's ear off or shaved their heads right down to the skin they should be pretty happy with their new cut!