1. be proffesional, look like a ref, act like a ref (NO shooting in time outs!)
2. Be confident, don't show your mistakes. You will make them, don't go change shooting fouls unless it's an obvious false call (and that should not happen in the first place if you pay attention
)
3. call games, the best way to learn is to get experience. You can NEVER have called to many games
Have fun! :d