"If you could go back and talk to yourself at age 16, what 5 things would you say?"
(I don't follow directions well, and can't limit myself to five)
Listen to yourself, and I mean really listen. Don't let others tell you who you are, and don't jump at the first thing that looks better. Really.
You think you're pretty smart, and you may be right; so what? A life of the mind only is barely subsistence. Try to root yourself in what and who is important to you.
The long hair: really, really, really, it's a bad idea on you, and none of your friends will tell you this.
Getting the hell out is a huge opportunity. Don't internalize abuse such that you don't realize it. You deserve better than wasting any more years of your life being abused.
Pretty is pretty. Don't miss out on opportunities because you let other people convince you otherwise.
Oh, yeah, and your taste in music rocks, and will continue to rock. By more records!
Be honest. Really, this is the single most important thing.