1. Cut your main fabric pieces:
2 - 11x12 in. pieces for the inner pockets
2 - 11x14 in. pieces for the outer shell. It would be fun to have different colors for the inner and outer sides of the shell too.
Also, think about what kind of closure you would like to have (or if you want one at all). I made a tab with a button on the outside, but a magnetic snap or velcro would work equally as well. If you opt for a snap it should be inserted in step 2 (follow instructions on snap packaging) before the pockets are sewn to the shell.
2. Fold both pocket pieces in half lengthwise with wrong sides together; and press. Align the long raw edge (arrow points to this edge in the photo below) with the short side of one of the shell pieces; right sides facing. Sew around just the 3 sides that have raw edges with a 1/4 in. seam allowance. At the corners, leave the needle in the down position and pivot the fabric to make sharp corners. Leave the folded edge open as in the photo. Repeat for other pocket. It will look like this:
7. Pin all the layers together. As a reminder to myself not to sew all the way around I like to leave doubled pins where I should stop:
8. Now sew around the edge with a 1/2 in. seam allowance, stopping where the double pins are to leave a space for turning the fabric right side out. Clip the excess fabric at the corners and turn right side out. Gently poke the fabric at the corners so you have a nice rectangular shape and press. Topstitch around very close to the edge and your wallet will look like this: