Find inspiring pair of pajama shorts! hehe. okay, so that's not really necessary, but that's just how it worked out for me! :P
Make a pattern. I took a picure of the shorts, blew it up on the computer and traced that to make my pattern.
Start assembling! The hardest part was sewing the wings onto the body... i poked myself so many times!
Add the little details that bring it all together, and viola!!