This is some advice that I gave in another answer but it applies to you too!
Play as hard as you can all of the time. This sounds obvious but a lot of players will stop trying when they aren't succeeding at something. Coaches notice who is giving 100% and who isn't. Be one who is!
Coaches also like to see players that are dedicated and want to make the team. You can show this by always hustling into huddles, to shag balls, to get water, etc. Keep a good attitude all the time and be coachable. This means that when a coach gives you direction, show that you accept it and say thank you. Don't be afraid to ask questions either. The coach will be impressed that you have been thinking about it and want to know the answer.
Since you are a more experienced freshman, show your confidence on the court. Coaches will see that confidence and like it!
Hope this helps!