Some people who are easily beaten in singles, can smoke their opponents in doubles. Tennis players who dominate in doubles often share one common skill: they serve smart by mixing up the speed and placement of the ball.
Mixing up serves is a good thing in doubles. However, be aware of how those changes help and hurt you and your partner at the net.
Serving out wide can put your doubles partner in a vulnerable position if you use the serve too much. It's tough to poach the ball as the net man because the opponent has the alley to hit the ball into and the ball has the potential of coming back with some serious angle.
The best bet is to go down the "T" or right at your opponent's body. If your opponent doesn't like being stretched out far and hitting cross court shots, it can be a plus for you and your partner to serve wide. However, you need to look out for more returns hit down the line or cross court with better angles.
Serving Down the Middle
By serving the ball down the middle of the court, your opponent has less of an angle to return with. When they return the ball down the middle you have a better chance of covering the shot. It also puts your partner in a much better position to poach the ball.
Going right at their body forces them to get out of the way and sometimes they'll only be able to block the ball back, which gives your partner a lot more time to step in and take the easy shot. You would be surprised how many people underestimate the "in the body" serve.
Aces might look better, but these types of serves are very effective. When you serve right at the opponent's body, they will try to move out of the way of the ball and end up off balance.