Play SMART instead of playing WELL.
People might think these are the same things but they are very different. For instance, hitting your biggest weapons is called "playing well". But this is not how you win matches. Playing well only works when you feel confident and you are playing someone as good or worse than you. However, "playing smart" means you have strategies to win. "playing smart" works even when you are not playing your best tennis. I am a 4.0 player and I faced a 5.0 today. The skill difference between us is huge. But I played smart- I made a plan to moonball+grind+slice to throw him off guard. I still lost but the score was 7-6, 7-5 for him. Playing smart gets you better results.