You’re going to hear the word “consistency” a lot when it comes to playing tennis. Understand that consistency means you hit the ball in more than your opponent. Your forehand, backhand, volley, and serves all have to come together.
A good way to set yourself up to play consistently is by paying attention to your grip tension. On a scale from 1-10 (1 being the loosest grip and 10 being the tightest grip) you should be gripping your racket at about a 5/6. This is to help you stay loose and swing the same way no matter where you are on the court.