If you have short hair, I would recommend using a smaller curling iron and curling all of your hair (not just the hair that is sticking out from the cap). I would do this by creating a spiral curl, where you literally wrap your hair around the curling iron rather than clamping it down and rolling it up towards your head. Here is an example:
For medium length and longer hairstyles, as all of my friends know I love the low side bun or ponytail. You can either curl your hair first or wear straight, but I would recommend cover the hair band with a piece of your own hair. I like he side bun/ponytail because people will be snapping photos of you all day long, and with the cap on your head, you may not want all of your hair pulled off of your head and your neck. One thing to consider is that photos will be taken of you from all angles, so plan your hairstyle accordingly. Even the sideways french braid video I posted under Braids Aren't For Kids can give you some ideas for your exciting day!
My advice is to play around with different options. Maybe instead of a side ponytail, just wear your hair swept to the side. Or if you want bigger curls, pick up sections and spray underneath (you can lightly backcomb for a bigger effect). Try to stay away from the perfectly curled hair or the intricate up-dos to avoid looking like you just walked out of prom (whether that was a 5+ years ago or 5 weeks ago).
Congratulations!

