Make a Navy costume piece, a school uniform top, or extrapolate to make your own article of fashion!
The best part about this is that it's totally washable; and the shirts to use are really inexpensive! If you go to Goodwill/thrift stores/whatever you can probably find good shirts to use if you look, but it may be hard to get a plain shirt for the base, and you might have the same problem in department stores (plus, it might get pricey). I got mine on Amazon for really modest prices!
I made this top for my Anime Boston 2010 Sailor Saturn cosplay and designed it to be comfy, lightweight and easy to move around in AND still have a costume on a student's budget.
Turn your collar base shirt inside out, and smooth it flat (by iron or by hand). Make sure that there are no creases or wrinkles, and that the collar is centered, along with the rest of the shirt; you can use any vertical seams as a guide. Find the center of your collar and mark it with your marker, which should be a washable one or a fabric marker.
Cut off the bottom of your shirt until you have a piece like the one pictured; cut enough so that you will have your desired collar length plus seam allowances, which may be greater or smaller depending on how you want to sew it or what you want it to look like. Cut the arms off of your shirt on the inside of the seams so you have one block of fabric with a neck-hole in it. Now you should have three pieces of fabric, just like the picture. We won't use the sleeves in this tutorial but you can save them for extras for this or any other project you have in mind. I needed them for something else, so I set them aside for later.
Fold your piece in half. Make sure that the rims of your shirt collar (we're using this as a reference point to find the exact middle of the fabric) match up! (You can also do this with a ruler instead of folding your fabric.) If you are a stickler for this sort of thing, you can cut off any big length differences to make both sides perfectly even, but you can also take care of this when you sew the seams if you intend to do so. I would highly suggest making seams if you want a traditional-looking uniform collar, as it looks more professional and neat.
Before you go on, make sure your shirt is inside-out! If you're marking your reference points in marker, you don't want them to show up on the finished product (like mine probably will, because I'm a dummy and didn't check which side I was working on.) Mark on your shirt where you want the tie or point on your sailor collar to be (the point where the fabric will form a "V"). The ruler helps make sure the collar will be centered on your chest, not leaning far to the left or right.I have done this in fabric marker, which is unfortunately purple so it's a bit hard to see. With that done I started thinking about how I wanted to cut it, if I wanted a straight or scooped edge, things like that. I used my straight-edge for the straight concept lines so I would be sure I wasn't about to cut an unintentionally curvy line.
*Note that if you want to make a tied collar, you will want to cut your collar piece more like a Y than a V so you will have enough material to tie it with.
BEFORE YOU CUT BE SURE YOUR FABRIC IS STILL CENTERED. It helps to pin the two sides together when you cut, but I didn't do that again because I'm a dummy and I was excited to finish this project.
Then cut the other side of the V! You might want to cut off the original shirt ribbed collar, you might not, it's really up to you. Depending on what details you want to add you might even cover it with something!
After making sure that everything is the way you want it, sew the seams! You might have some difficulty with the inner V, it might help to make a teeny-tiny nip at the point so you can fold the fabric over. You could also:
-Cover it with bias tape, lace, or trim
-Blanket-stitch the edges for a fun look
Or decorate it however you like!
Once your seams are done, you can start thinking about decorations. I wanted a collar with a stripe, because I'm making a Sailor Saturn cosplay, so I used white ribbon. I pinned it where I wanted it and then sewed it on.
You can make a bow or tie using any method you like. I made a large bow in a different color using methods I picked up from different tutorials elsewhere on CO&K, put it aside, and sewed it on by hand when everything else was finished.
Now, our collar is basically done!
Cut your shirt however you like. I thought I'd need extra fabric to make matching gloves for this costume so I ordered long-sleeved shirts and ended up not needing them, so I just cut off the sleeves.
Once you have your collar the way you like it, position it on your shirt. I lined up the shoulder seams of the two layers of fabric as a guide. Depending on what kind of uniform shirt you want, you can use just a regular t-shirt or a long-sleeved one. Sew the collar in place, and you're done! Add any details you like. You can add buttons, a pocket (or get a shirt with a pocket and modify it for the look you want), make bands for your shirt and put them on the sleeves! A simple Google image search for anime or Japanese schoolgirls (maybe with a mature content filter on!) would give you a great starting point if you want ideas.