If you are serious about improving, make sure you read the this too: How-to-Improve
The coaches know that everyone hopes to get something different out of their high school tennis experience. So, we don't put our goals onto you. But we will help you achieve your goals. This page gives you some guidance on how hard people generally work to achieve each goal. Ask a coach if you have questions.
The "Get Good" section is a lot of tennis, ranging from about 10-20 hours per week. For players who want to be one of the top few in the league and are looking to play college tennis (even Division III) will need to spend that 10+ hours a week. For those of you lucky to be more athletic than the rest of us (lucky you!), you probably don't need to do quite as much. But you should still get a mix of practice, matches and lessons to make sure you are learning proper technique.