The points in tennis have gotten shorter and shorter. A great concept to increase your chance of success is to focus on the first two hits of each point.
Try to hit a good serve (preferably first serve) and a good first shot on as many points as possible. Use the same idea when returning serve-good return, good first shot. Most of the points (75% according to a recent study on the pro tour) will be over before you have to do anything else.
Practice this concept with another player by only playing the first four hits and see how many points you are able to execute with each player hitting two good shots.
Remember to try to hit the ball as you would in a point-don't try to hit winners immediately and don't try to just get the ball in. Use your regular shots and build confidence in your ability to get to this stage of the point more than your opponents.