A couple of things you might find helpful w/ your first AR:
1.READ the forums here @ AR15.com! Such a wealth of info here!
2.Put together a basic tool kit of maint. and cleaning goods for your AR.
3.Secrets about the gun? Nope...it shoots where you point it and goes "BANG" provided you have decent ammo :)
My M4 upper pre-ban came direct from Bushmaster a few months ago and I have not had one single issue w/ it. Rocked about 400+ rounds thru it Friday and enjoyed every shot!
You'll enjoy yours as well, AR15Mudder!