1. Don't Be That One Overly Edgy Kid
Enjoy your life. You don't have to look tough or edgy by always wearing black or listening to music you don't even like that much.
2. Don't feel like you always have to be in a relationship
If you end up dating someone, it should be because you really like them, not because all your friends are doing it.
3. Don't be so hard on yourself
Sort of goes hand in hand with the first one, but teenagers tend to sometimes hate themselves.