Be Aware of the Strike Zone
Pay attention to your opponent's strike zones. For example, if you're playing someone who can handle your kick serve, start hitting slice serves. Mix up the serve and find out what works against certain players.
More: 5 Steps to a Better Kick Serve
Let's say you're playing someone who is tall, returns well and hits groundstrokes well when he or she is at full stretch. Try serving at their body. Your opponent might still get some good returns back, but they probably won't be as powerful. The taller opponents have more problems when they are jammed with a serve or a shot.
Some of the shorter players will not struggle with that as much because they have less body to get out of the way. The out wide and high balls could give the shorter players some problems.
If have a big, fast serve and your opponent lobs them back deep into the court every time, it's time to change your strategy. Serves that have more spin and kick are harder to lob.
More: 4 Steps to a Faster Serve
Mixing in some slower pace serves with more spin could catch your opponent off guard. They might be forced to return the serve with a cross court groundstroke, which should help you and your partner move to the more aggressive net position.
Consider Your Partner
Before serving, consider what your partner expects you to do. Communicate with your partner about what serve you will hit before you hit it. Although you don't see a lot of this in club play, it can be a huge factor in the game. Let your partner know where you plan to serve so they can position themselves appropriately and not try to poach if you plan on throwing in an off pace slow ball serve.
In the end, adapt to who you are playing against and who you have as a partner. Mix up the serves so your opponent does not get into a rhythm. Find what works and be sure to attack the vulnerable parts of your opponent.
If you see them starting to lean in one direction or another on your serve, attack the open court. The main goal is to adjust your serve however you need to so your partner can attack the weak returns.
More: No. 1 Serving Drill to Keep Your Ball Out of the NetSearch for your next tennis event.