Congrats man! My kids are 9, 10, and 11 (going on 18). What I've learned so far is:
1) You will never know it all, don't try
2) Mistakes will be made, it's not a big deal
3) They're gong to hurt themselves, support but don't coddle
4) Lead by example, they'll emulate you, especially when you can't see it
5) Be honest, see #4
6) Show them you love them, it will be reciprocated in spades
a) Don't be afraid to be angry/disappointed/upset with them, see #5
7) You are also human, it's ok to be annoyed sometimes, you're not perfect, see #2
Enjoy the ride!