A few suggestions for embellishing your shorts:
1. Keep in mind how you're attaching your embellishment. If you can't sew, use a strong, permanent glue. You don't want to shed sequins wherever you sit.
2. If attaching studs, remember to fold the prongs over all the way so they won't scratch your skin. Placing them on the outside layer of pockets will prevent this issue.
3. Think about your activity patterns. Personally, anything lumpy or pointy on the back of shorts seems really uncomfortable to sit on! Also, if you tend to use your pockets, keep that in mind when embellishing.