I've used a paper bag that's the perfect size for a CD, but you can use bigger sizes and just cut them smaller and then sew them closed.
1. Measure your CD and cut away any extras that are in your way.
2. Fold the bag the size you want it, to determine where you're going to add lace or whatever you're using.
4. Stitch your lace in place. I stitched it on the "top" of the CD cover because it's the easiest. You can use Washi tape, scrapbooking paper, anything that tickles your fancy. Just remember to not stitch through both layers, otherwise your CD cover will be closed. (I'm not implying that you are an idiot, but maybe you are lazy like me...)
5. Now, if you had a big bag and had to cut away some of the bag, now would be the time to sew those sides closed. Mine was a perfect fit, but I still like to stitch things so I did it anyway. I used pink and grey thread and stitched around all three sides.
7. Stick'em on!