My friend bought this great old dress on the side of the road for $1. It was handmade, probably from a pattern, and altered a few times.
The zipper was so corroded that we couldn't unzip it, and after some trying the zipper pull just crumbled off! Turns out the dress was tinier than it looked and didn't fit either of us. I said i could fix it so she said i could have it.

I used this dress to experiment all these different alterations on, and now have a dress that i like a lot. Take this less as "How to Make a Dress That's Exactly Like Mine," cause honestly who cares and why would you want to, and more as

-sewing instruction
-tailoring practice
-pattern making/designing, without actually writing out a pattern
-getting comfy altering your own clothes (i could write all day on what i think of ready-made clothes. instead i'll just promote learning how to tailor and redesign your own.)
-other

I won't assume you have prior sewing knowledge but am also gonna avoid technical sewing explanations, for the most part. That stuff can easily be looked up online, and also there are many ways to do most things.
"How?"
"The way that works," you know?

If you don't have a sewing machine, it's fine. Sewing by hand is social and fun, gives a different look and allows a different kind of control, and makes good idle activity for the bus.

It wasn't difficult it just took a lot of time. Who cares about that though, right? Not you- you've got a yearnin' for learnin' and that can't be taught in school!

Step 1: Before, and What I Did

Here's what the dress looks like now. The photo's weak but let me tell you, this dress is great. It was great before, but nothing like how it is now!

I don't have a Before picture. Before, it had
-no straps
-no ruffles or purple along the top (bodice ends with the blue cups)
-skirt longer, and all the same length
-bodice was smaller and had a side zipper

It was rad but way too tiny. The color combination on the skirt's tops, but the high waist and ruffles completely covering the outside looked cylindrical and sad.

Here's what i did
-enlarged the dress from the ribcage up
-added straps
-added embellishments to the top
-changed the skirt
-replaced side zipper with back buttons
-reduced the cup size/shape
-added hanger straps

Step 2: Altering the Skirt

The skirt was made out of lovely material, but way too much of it. Maybe that looks fantastic on someone, but definitely not on me. Besides looking hella dumpy, i knew that skirt would get destroyed if i left it that long. Not that i can't have nice things, i just don't want nice things that are a high-maintenance pain in the ass.

I decided on a skirt shape that's highest at the center front, longest in the center back, and swoops down on the sides. With the dress on, i put a safety pin where i wanted the highest point of the skirt to be.

With the dress on my dress form, and the dress form's height set to my my height, i put a pin on the center back, where i wanted the two side swoops to meet, and cut from the front pin down to the back pin. The dress form makes this so easy, but if you don't have one, putting the dress on a hanger, maybe with more specific safety pin marks, will work.

Took it on and off a few times to be sure it was the right shape, saved all the trimmings for later steps.

The blue ruffled fabric won't fray at the raw edges, but i didn't know about the purple, so i ironed it in and hemmed it.

Step 3: Resizing the Top

At first i thought i'd enlarge the top by buying new fabric to match the blue on the bodice, and adding panels to the sides. But that's boring and i'd wanted to make a mostly open-backed dress for a while, so i decided i'd open the back up to resize it, and put the closures there somehow.

-First i ripped the stitches at the corroded zipper, took that whole thing out, and sewed the side seam shut.

-Then i sliced down the center back of the bodice to the skirt, and put the dress on to check the fit and see how far apart the left and right sides of the back should be.
I tend not to use numerical measurements and prefer using myself as a unit of measure. It's because numerical measurements don't sit down, move this way and that, eat, retain water, wear the dress differently on different days, have a crooked spine, you get what i mean. It takes more effort to pin things in place and double check when doing it this way, but i find that the results fit way better.

-Took the dress off, ironed the newly cut back edges inward and sewed them down.

-I positioned the top front where i wanted it, and had my roommate measure how far apart the top back center panels should be. Pinned the dress back onto my dress form with the back edges that far apart. This was the most numerical thing i did the whole time, possibly the only numerical thing i did the whole time!

Step 4: Straps, and Details

Using what i'd cut from the skirt, i made edging that doubled as straps. I used only the scrap because doing that's the fun challenge to have, and also because that way all the alterations would match perfectly, at least in color.

To make this strap/edging i cut even strips of purple fabric, ironed both sides inwards, and sewed them down. At this point i still didn't have a plan for what the dress would look like;
I just made a few of these very long strips to pin and experiment with, and would cut them down once i found something i liked.

I also used parts of the ruffles, obviously, and the purple edging runs down both sides of the back. The photo is of what it looks like done.

General sewing opinion/fact- The step that includes experimenting with designs, getting parts to match, and especially pinning should be the step to devote the most patience to- yes, even more patience than should be devoted to the actual sewing! Sturdiness, a good fit, and a style that works for you -not technical things- are actually what determines whether or not the thing's gonna get worn.

Step 5: Resizing the Back

After weeks with my dress hanging like this on my dress form, I decided
on how i wanted the back to close. It mimics the bows on the front of the skirt, as i'm sure you noticed immediately.

The back is made from three pairs of triangles pointing inwards, with buttons on the triangles to the right and buttonholes on the triangles to the left.

They're positioned in the places that will make the dress fit the tightest, and stay in place the best, to reduce pressure on the straps and minimize fraying and wear.

Step 6: Triangle Assembly

-put a big piece of paper inside the dress, position the back halves the distance apart that they'll be in the end, and draw how you want the finished triangles to look.
-take the piece of paper out and cut out the paper triangles. Using them as a stencils, cut out two of each in fabric.

-Pair up matching triangles and pin right sides together. Sew the pairs of triangles on the edges that will become the top and bottom. Trim the tip off the triangle, turn inside out (be sure the tip of the triangle is all the way out by pushing it from the inside with a pencil), and iron flat.
-Take some sturdy fabric that's not too thick. Cut triangular pieces that will fit inside each triangle and extend out the open side about 1/2"
-Keep these sturdy pieces of fabric inside the triangles when you add the buttons and button holes.

Step 7: Buttons and Button Holes

I used that piece of paper again to reposition the triangles where i'd originally drawn them, pinned them in place, and tried on the dress. My roommate pinned the triangles tightly in place, and marked where the tips lined up using safety pins as markers. This determines where the buttons and button holes should go.

-Sew the buttons on. How? The way that works, that's how! I prefer to sew buttons with a needle and doubled up thread. Maybe you prefer sewing machine, dental floss, or instead of buttons- hooks, snaps, leather from your old harness, chinese finger traps with fingers in them

-I will help you out a little with the button holes though, even though we're on the internet and sewing information is everywhere. The thing to remember is that when buttoned, the button will pull on the button hole from one side. So if you center the button hole over where you want the button it to be, you'll end up with something that's shifted slightly looser in the end. When positioning the button hole, have the inside end lined up with the sewn center point of the button.
-To make the button hole i pinned a straight pin where i wanted the hole to go, and used that as a guide to sew around. They make button hole feet for sewing machines. Those work well but aren't necessary. To make button holes I use a tiny zigzag stitch with a very short stitch length, rather than a straight stitch. You can also mimic this stitch by hand. All that matters is that the hole doesn't become too small for the button, and that it doesn't fray. After the hole is sewn, i remove the pin and very carefully slice between the sewn sides with a razor blade.

The button should be a tiny bit snug at first; the hole will stretch slightly over time. You can always sew the hole smaller though- it's so easy that you already know how!

Step 8: Insert Joke About "boning" Here

Months later when i finally had cause to wear this dress i realized that like many items from this time, the cups are super high, puffy, and ridiculous. Basically I looked like a villain from the movie Hairspray, which is amazing style, so i let it be. Eventually i noticed how easy it would be to fix.

-The bodice of this dress has boning -basically flat wire coated in rubber- down the front and sides, held down with little white sheaths. I pulled the boning out a few inches from the bottom of the sheaths, folded it up, folded it again so it wouldn't stab me, and pinched it in place with pliers.

-Sewed it down with doubled up thread (my favorite), and used some of that purple edging to create a cover for it.
-The edging is folded in half the short way, then down again to hide the raw edge on top, and sewn using a Frankenstein Stitch (aka a wider version of the stitch you used if you sewed the button hole by hand). This stitch is good for things that you want to stretch or don't want to fray.

Yes! Job well done!