Started out 5th and 6th grade boys summer leagues - felt totally lost the first few games.
Echoing some things already said:
- Always get your hand up -
- Strong whistle - gives you and everyone else confidence
- Call the obvious
- Try whatever technique helps you to relax - (my first trainer said "keep telling yourself it's just basketball, and you KNOW basketball.") For me getting there on time or a little early allows me to get ready without rushing.
- Slow down, slow down, then go really slow, then still slower in your responses to violations and fouls.