I have braces! Helpful tips:
On the day that you first get them on, you think, "oh, this isn't painful at all!" Just wait. Days 2 and 3 I was holding an ice-pack to my face. Once you get past that, it starts hurting less until eventually it doesn't hurt at all. Then you go back to the Orthodontist to get them tightened! (New, tougher wire.) Then it hurts all over again. Each time you go back to get them tightened, the initial pain goes down.
Remember to brush your teeth OFTEN and chew xylitol gum if your orthodontist says it's OK. Xylitol naturally kills bacteria off your teeth, helping them to not get cavities.
Don't slack off on doing what the orthodontist tells you! It may sound like a boring, unnecessary routine, but DO WHAT THEY SAY and your braces will get off your teeth faster. I'd say the hardest discipline part of braces is wearing rubber bands. They hurt so much and you have the temptation to just take them off! Don't. Your orthodontist will be able to tell and will be disappointed in you, not to mention he/she might have to put unremovable springs in your mouth instead of bands.
Orthodontists tell you to not tear things with your teeth with braces (pizza, meat, whatever). But it is not life or death. This is the one rule I can say that you could get away with occasionally breaking. You have to pay attention, though; tear carefully; don't try to tear something super tough like beef jerky!
NEVER, NEVER, NEVER NEVER!!!!!! EAT POPCORN!!!!!!! There are horror stories of kids getting kernels stuck in between the braces and their teeth. They have to go in emergency-style to get it out. The ortho actually has to take off the braces to remove the kernel!
DON'T EVER EAT POPCORN WITH BRACES!
Bring a toothbrush with you to school if you are not homeschooled. Brush after lunch so your braces don't have food in/on them (gross, I know).
If I think of any more I'll be sure to let you know.
OH! Don't eat hard things like jawbreakers! (There is a reason they are called that!)
If you do, you might accidentally pop a brace right off your teeth!