There's a full tutorial on this at Sew Mama Sew, so I'm not going to rehash the details here. I made mine smaller since I was trying to use up the fabric from my niece's duffel bag.
Because my version is smaller, I used fewer grommets (8 instead of 12). I also added some stash pockets on the outside - the front pocket spans the width of the bag, the back pocket does the same but I sewed up the middle to divide it in half.
The lining is nylon, which is slippery as hell, but worked out well!
It's a nice bag to grab and go, the drawstring closure through the grommets adds a nice way to keep things inside, and it opens wide so you can get at whatever you need.
