Your ability to do a good closure can easily make or break your doll clothes. No pressure.
This is something that is both easy and hard. It's very easy to explain, and very easy to understand, but especially when you're working with the smallest of dolls, your fingers need to get what's called 'muscle memory' to be able to do it well so it can be frustrating for newbies!
First I'm going to run down the list of different types of closures and the pros and cons.
What it's good (and bad) for
Pros: Easiest to find, can be cut to size, lets you adjust a closure slightly more/less to fit doll body variations
Pros: Can be cut to size, lets you adjust a closure slightly more/less to fit doll body variations, no thicker than snaps.
|Snaps||Pros: Come in different sizes, can take the most 'pull' before coming undone.
Cons: Need to be sewn in by hand, takes longer to sew in than hooks.
|Hooks||Pros: Needs the least overlap, can be placed to have a perfectly flat edge-to-edge closure.
Cons: Comes undone very easily, hard to position just right, needs to be sewn by hand.
|Zippers|| Pros: Gives a smooth closure with no overlap
Cons: 'doll sized' ones have such small parts that they break very easily, and replacing them is almost impossible. Even the smallest doll zippers are relatively chunky on dolls smaller than 1/4 scale. Very hard to sew in.
|Buttons||Pros: Can look the most authentic in scale.
Cons: Tiny buttons are easy, button holes are the problem. Buttons work in situations button hole stitching isn't needed: a non-fraying fabric, or if a button-and-loop closure is used instead.
Pros: So pretty!
As of the time I'm writing this there's only one pattern out of about 300 that I give instructions for with an optional zipper (1/3 Super Stretch), zero with actual buttons and zero with actual frog closures. If you want the look of buttons and frog closures, those are best done with clever fakery (you sew them on and stick the closure elsewhere).
Tiny zippers and buttons can be done, but I recommend them only on art dolls that will rarely if ever be redressed. This is because they damage very easily so if you're taking them off/putting them on, it's more of a matter of 'when' not 'if' they will break. When they do, replacing them is very difficult or impossible.
For most of us, velcro, snaps, and hooks do great. They take being done up and taken apart very well and can easily be replaced or repaired if necessary. Clothing closures for all 3 are set up the same way, just with a little more/less overlap depending on the closure.
That means once you learn to do a closure, you can easily swap between velcro, snaps OR hooks without needing to learn a new skill. Nice!
So let's get to it: First, put the clothes on your intended doll. Fold under the edge that will be the 'top' (doesn't matter which side, I just go with whichever looks nicer). Pin it closed to simulate how it will look when the closures are added.
(pins recolored in red so you can see them more easily)
You want it to align roughly with the spine. You can also do it a little to one side so that the closure (velcro, snaps, hooks) will sit on top of the spine and be centered.
Once you get it nice and straight and smooth, check the fit:
Not every piece of clothing will have the same fit, some are designed to be tight and some are designed to be baggy. They key is you want it to look the same all over. No spot where it's tight vs the rest being baggy, no lumps, no wrinkles.
If you need to adjust the fit, take the pins out and try again. When the clothes look nice, you're done.
Mark where your closures will go in. For example, I'll take a fabric marking pen and put a dot on the inside of the closure on both sides where a snap or hook will go, or a straight line if I'm sewing in velcro to mark where I want the edge of the velcro to line up.
Remove the pins, take the clothes off the doll. Hem the edge of the side that will be the top and sew in your closures--if you're doing velcro, you can hem and sew in at the same time.
If you're sewing one of my patterns, you'll probably have a good bit of extra fabric there. This is because big fingers have an easier time with more than less, and because all of the patterns are done with the biggest closure (thick velcro) in mind. You can easily trim off what you don't need, where adding more is much harder!
Wait, wait, not done yet. I have one more tip for this Materials Monday!
I love thin Velcro, but it's a PAIN to get my hands on. There is a kind of thin velcro you can get everywhere, but it's got glue on the back. In a pinch, you can still use this stuff, IF you use it the right way.
The trick is, you can't sew in glue-gummed velcro. It'll mess up your needles and your machine if you try. You need... MORE GLUE!
Specifically, this stuff:
Or possibly another brand of clear fabric glue. If you want to know more about fabric glues, read this article.
You'll want to smear a thin coat of glue all over the glue already on there. This glue is chemically similar enough to the stuff already on there that it bonds instead of just sits on top of it and separates when force is applied, which is what would happen if you used, for example, white fabric glue. So if you do this and the stuff isn't sticking, you probably used a chemically incompatible glue.
Unlike the other closures, this works best if you do it on the doll.
Trim your velcro pieces to an appropriate size. One big piece is rarely the way to go, I like to use multiple small pieces to keep clothes flexible. How wide you want your strips to be will depend on the doll size. In Monster High and Barbie dolls I usually use about 3/8" wide strips, in 16" and larger dolls I use about 1/2" wide strips. If you're not sure, check them against the doll to make sure.
Take the velcro apart and carefully apply a coating of glue to the gummed side of each velcro section and place in the closure.
Be careful to make sure that when you put the other side of a velcro section in that it lines up exactly with the side you already have in. This is more important than exact placement, because the glue is still sticky. That means, once you have all of the velcro parts in, you can slide them around a little bit until everything is smooth and perfect, like so:
So flat. So smooth. The perfect closure <3
Once everything is perfectly in place, pin the closure shut. This is to hold everything in place while the glue sets. DO NOT REMOVE THE CLOTHES UNTIL THE GLUE IS DRY. If you do, you'll just rip the velcro out and have to do it over.
After the glue is dry, take the clothes off. I often find that the corners of the velcro need a touch up of glue because those are the places your fingers are most likely to take the glue off as you're applying it. You can touch up glue by putting a drop of glue on a pin and applying it anywhere your initial gluing didn't take. Once any touch-up glue is dry, you're done!