One of the most important concepts a tennis player will learn is to take control of the point.
Obviously, we cannot control everything that goes on in a tennis match. However, if you are able to control the point more often than your opponent, your chances of success greatly increase.
Controlling the point can happen in many different ways. Hitting a good serve or return of serve can get your opponent in trouble right away. Using a good crosscourt groundstroke at the beginning of the point to get your opponent running is another great way to control the point. Using your position by moving forward when you hit a good shot takes time away from your opponent and helps you control the point. Hitting the ball at the peak of the bounce or on the rise is another way to take time away. Keeping your shots deep can push your opponent back and give you the ability to control the point.
Finally, adding racquet head speed and hitting your shot with more pace can put your opponent on the defensive, giving you the upper hand.
There are many other things you can do on the tennis court to get control and keep it. Try to focus on the basics such as getting your first serve in, moving your opponent around, and staying aggressive when they are in trouble, before ultimately hitting that shot that wins the point. If your opponent has to work harder than you in the match, you have succeeded in taking control of the point more often, and will likely give yourself a great chance to win the match.