Many problems in a tennis match occur because of indecision.
A player is faced with many choices when they are about to reply to a shot that’s hit to them. Direction, speed, depth and spin are just some of the decisions that need to be made in a very short period of time. My advice is to use your practice drills during a point.
For instance, most high-level singles players practice some version of "lines and crosses", where one person hits all shots down the line and the other hits all crosscourt shots. Pretend you are the crosscourt player in this drill and hit all of your shots at the beginning of the point in this direction, regardless of the direction your opponent hits the ball. Many times this will get you starting the point in a manner you are used to, and will likely result in several good shots that are hit decisively and instinctively.
Another drill that’s often used in practice is the "deep" drill. Play the point thinking you are going to hit three or four shots in a row past the service line before trying to win the point. These ideas that you convert from practice to match play will help eliminate the indecisiveness that can occur in a real point.
Using your muscle memory and habits in your matches will help you execute better and react more quickly when it gets to crunch time.