Tennis is a great sport, partly because you only need one other person to go out and hit or play.
In addition, you can also do a lot of things by yourself to practice and improve. The most obvious is to go out and hit serves. Since the serve is the most difficult shot to learn, and also, the most important shot in the game, this is a good place to start.
Another great thing to do is to take one ball in your hand, throw it underhanded up in the air and slightly in front of you, and then hit either a forehand or a backhand to a specific spot on the court. Hitting against a wall or backboard is another great practice activity. The ball will get back to you almost twice as fast compared to when you are hitting back and forth with someone, so this will help you recover and react quickly, improving your overall preparation skills.
A ball machine is an awesome tool to help develop good timing, rhythm and footwork. The modern ball machines can vary the direction, spin and speed and make it feel like you are playing a point. A portable machine can cost $500-$1,000, and many still have a lot of the features that simulate hitting or playing with an opponent. Don’t forget that you can also do some footwork and conditioning drills with or without your racquet in hand, and simulate some of the movements necessary to make you successful in your next match.
Practicing on your own in this manner can improve your physical skills and also build additional confidence in your game.