Practice before try outs to ensure that you are on top form by that time.
Turn up early to try outs it will display your eagerness to play the game.
Introduce yourself to the coach and try to appear well mannered.
Display a good knowledge of the game to both your team mates and your coach.
Try to stay within the coach's line of view as much as possible as this will help him to observe your potential.
Practice at least 3 times a week in your house or local gym. Always try to practice with people because around 60% of the shots you make may not go in and you won't have much experience with assists/passes and being a team player.
Most coaches want a team player and one that knows what he does. Don't try to show off and use any of your streetball skills too much.
Leave a good impression. Make assists be on top of defense, try making some turnovers.
Never get caught standing around or looking at your coach. Always follow your instincts when it comes to an open shot or layup.
Feel confident--as if you own the courts. Drink a lot of water and the week before a tryout don't play too much Basketball.
Don't yell at your teammates if they mess up a play simply encourage them.