You probably all know how to do this already, but no one's posted a thread on it yet, so why not be the first to do it?
What You Need:
1. First, put the fabric down on a flat surface, with the ugly side up. (If it's reversable of the same, just put the side that you want to be the inside up.)
2. Fold over the top, like the picture.
3. Sew across the folded part, as close to the bottom as you can. It's a bit hard to see the picture, I'm sorry! The second picture is of the whole side stiched up.
4. After it's all sewed up, fold the fabric in half "hamburger ways." Be sure to have the ugly side out.
5. Sew up the last two sides. Make sure you sew tightly because the parts you're sewing are the bottom and sides of the bag. You wouldn't want your things to fall out of it!
6. Take the cording (or ribbon, or fabric strip... something to be the handles.) and pull it through the "tunnel" you sewed first.
Here's it when it's all done!