When you are in the volley position near the net and your opponent is "hammering" the ball at you, think of yourself as a fielder in baseball and your opponent as the hitter. Remember that the fielder has only a glove to work with. The glove is used to "catch" the ball, not to "bat" the ball. Thinking of it this way can cure the usual mistakes a player makes on his/her volleys of pulling the racquet back too far and swinging at the ball. Watch a baseball game sometime and observe the simple motion of a "glove catch." Then try this simple catching motion using your racquet on the court.
Think of yourself as a "batter" when you're hitting groundstrokes and service returns that are slow to medium in pace. See yourself as a "bunter" when returning your opponent's fastest serves or strokes.
Observe how the baseball pitcher observes the runner on first base before he throws the ball. He (or she) is watching to see if the runner is going to "steal" a base. He is looking to pick the runner off with a quick throw to first. When playing tennis, you must always have a general idea of where your opponent is before deciding just where to go with the ball. You are using your peripheral vision to accomplish this.
In doubles, you and your partner are at the net when your opponent sends a high lob down the middle of the court. You call "MINE," allowing your partner to move out of the way and indicating that you have the situation under control. The same rules apply when out-fielders converge on a fly ball in the outfield. They call one another off the play when they have the catch in sight.
In general, you can look at many other sports and use pieces of them to help you play better tennis. Try these "visual pictures" to your advantage.
Good luck on the courts!