Many players just don't understand why they play so differently in an actual match compared to what they do in practice. One of the problems is that it is extremely difficult to simulate an actual match situation in practice.
Some small adjustments to your practice may help this. Try doing your normal hitting drills but then play the last part out as if it is an actual point. Add the competitive aspect (keep score) to your technique and footwork during practice so that you have a similar approach to a match situation.
Another great challenge is to serve and return serve, and then practice your shot or strategy, rather than just doing it off of a feed. Hit the serve medium speed and the return medium speed so that it is a 50-50 situation after the first two shots. Then try to use your next few shots as you have been practicing. Although you may not get the same feeling as a competitive match, at least you are conditioning yourself to expect the point to last a few hits and relying on habit and instinct, as you should be doing when competing.
The closer you get to imitating what happens in a match, the better your practice will be, and the more likely you will be successful when you are out there keeping score and playing for real.
Steve Annacone, USPTA Elite Pro, is the Director of Annacone Tennis, www.annaconetennis.com and MyHamptonsPro, www.myhamptonspro.com throughout the Hamptons, NY. In addition, Steve and Miguel Coelho have introduced the JET (Junior Elite Tennis) program at the Tucson Jewish Community Center (Tucson, AZ) for high level players ages 8-18. Please contact Steve at firstname.lastname@example.org