you should have trusted in him more

 Just hang in there. There's a lot of bad stuff coming up, and its going to be hard. You're going to hurt yourself and your life will never be the same. But once it's all over, when you can give your younger self a chance to change something, you won't.

 Dont show off when your drunk and jump over the balcony (even though it got you laid) Its not worth it

 He's not waiting for you. He's out there screwing around with any girl he can('t) get. Move along now, little girl. Your young and he never promised you anything. Duh.

 Stop wasting your time trying to change. You're better than what you want to be. I wish I could be what I was when I was you.

 Stealing leads only to trouble, it may be exciting or whatever but, I think it's counterproductive

 you will marry the guy that is "out of your league" from college.

 Tell him you love him. You won't lose him as your best friend, you'll keep him and get an amazing boyfriend.