First off, with the exception of one high school home ec class, and all good faith efforts by my mom, I am for the most part a self-taught seamstress. I read a lot on the internet, and made a lot of mistakes. The seam ripper is my bestest friend. Now... On to my first tutorial.
I'm using pre-quilted fabric, nylon webbing for the strap, iron-on velcro, thread, and letter beads. That's about it. Oh, and the pink rick-rack.
Trim if necessary (like if some of the batting's sticking out), and sew using a zig-zag stitch right at the edge. Fold up so the inside is out. I eyeball it - this one happens to be folded 6 1/2" up. Whatever looks right, depending on how long you want the flap to fold over. Stitch with a 1/4" seam, then zig-zag the raw edge, going up to the top of the fold.
If you have a fancy-pants serger, you can use that. I don't.
Turn right side out and press. Fold the edges of the flap in and press. Trim the excess, leaving 1/4". Zig-zag down.
Fold the top of the flap over 1/4" and press. Zig-Zag down.
This is the slightly tricky part, and if there's a better way. Let me know. Measure off 36" of webbing and pin where you want the handles. I tried putting them on the inside, but then it closed awkwardly so I just put them on the outside back.
Stitch on. I stitch around in a square, going back and zig-zagging along the raw edge.
Trim any loose threads. I like to press down the flap prior to ironing on the velcro. Iron on the velcro, and then sew on letter beads if you'd like. As soon as I find my Tacky Glue, I'm going to glue the rick-rack down over the raw edge on the flap.