Mix your shots up!! Easy to say, harder to do. Why? Read on!
Is your shot selection repetitive? Think it through. Is your opponent heading for your shot before you hit it? Cannot tell you how many matches out of the corner of my eye I would spy my opponent taking off for where the shot was going to go before I hit it. If so, you must change your shot selection. Part of changing your shot selection is good footwork and mechanics. For example, if you carry your racquet low and want to hit the ball hard you will to hit cross court to pick up the kind of pace you want. Therefore your opponent will head off in that direction before you hit the ball. So the first thing to fix is mechanics of forehand and backhand and then head on to footwork.
One match that is etched into my mind was a match with a young phenom whose speed was off the charts. My first setup on the forehand side I pinched the right corner. The next setup I automatically hit a V pass left figuring he’d look for the pinch. Nope, he was still back there in deep center court. Next setup, I hit down the line right, nope still there. The reason I remember this match is two-fold. One, he moved to San Diego and became a really good open player so I got lucky to play him early and two, he never adjusted to my shot selection but I sure adjusted to his coverage.
Back to shot selection. I used to have a rule I used against very good players. “Down the line and shoot bottom board, especially when I have the serve” was a rule I used back in the day. It was very effective as the down the line made the court bigger. If your opponent is comfortable with your shot selection, cross them up! Mix up the setups so they cannot take off before you hit it and be effective.