My pocket is going to be pretty small, so my zipper is too long. There are instructions on the zipper for how to shorten it, but I'll list them here just in case.
Figure out where you want your zipper to end.
I apologize for the lighting being crazy in the next pictures. I kept going back and forth between two rooms (sewing machine and ironing board) and one had sun coming in and the other didn't.
Cut fabric for the pocket that is twice as long as you want your pocket and at least an inch wider than your zipper. My zipper was 4 1/2 inches and I cut my fabric 6 inches wide. Fabric was 7 inches long, which means my pocket will be 3 1/2" x 6" finished. Make sense? (I hope!)
Next you stuff the pocket fabric through the hole you just made. This will likely make it look like you messed up. Not to worry, things look a lot better after you press them.
And now the finished product...
I've seen other variations to add a zipper pocket, so this is by no means the only way you can do it. If you have any questions or notice a hideous mistake PLEASE comment or email me and I'll try to clear it up. I'm still pretty new to