It is extremely important to get your first serve in and to get your return of serve in play. However, one of the keys to winning a tennis match is to get control of the point more often than your opponent.
In addition to making your serve and return of serve, try to get the opponent in some trouble by using depth, spin, speed, or placement on both of these shots. A good way to start is to hit most of your serves deep and to the middle of the service box and most of your returns deep and down the middle of the court. This gives you good margin for error (you likely won't miss these shots wide) and can often handcuff the opponent because these shots will end up into their body, forcing them to move out of the way of the ball.
Once you gain some confidence on your serve and returns, try hitting some spots closer to the sidelines (a foot or two inside is a good target) and get your opponent moving. This will open up an area of the court for your next shot and help you keep your opponent on the run. By starting the point with this idea, the rest of your game is likely to be better because the shots hit back to you will usually be more defensive, allowing you to hit from a more set position and to continue controlling the point.
The best players in the world are experts at using the first shots in this manner, while still make a very high percentage of first serves and a high number of return of serves. Follow this mentality and watch how the rest of your game improves!
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 email@example.com