By adding them to your repertoire, you should meet with greater success. Look for specific body movement characteristics of your opponent. Many players will offer a clue to their shot by lowering their lead shoulder on a drive or raising it when they throw up a lob. Watch your opponent's foot placement. Look for patterns in your opponent's game .
Many players become extremely predictable.
Some players will always try to pass down the line or crosscourt, regardless of the position of their opponent. Some will always lob when their opponent is at the net. Study your opponent's racquet preparation. Many players give a clue to their intentions by preparing their racquet differently for different shots, such as lowering their racquet early when lobbing. Visualize the court from your opponent's viewpoint.