Another really important thing.
It seems like a no-brainer, but you'd be surprised.
Be punctual.
Everything you do during clinics and tryouts reflects on you.
It reflects poorly on any athlete when they walk into a pre-tryout meeting, clinic, etc. even five minutes late.
Your school cheer/all star coach may not have cared about 5 minutes.
But there are plenty of coaches who when given a choice between 2 athletes will pass on the one who was 5-1o minutes late every day.
If anything, be early.
Also, the excuses that may fly in school cheer or your gym don't really matter. College coaches generally won't accept "omg, the line was really long at the SBux drive-through." No one cares.