One of the best ways to beat opponents is to take them out of their comfort zone and stop them from using their weapons. How you ask? By mixing up your shots.
For example...if your opponents are constantly lobbing you to pull you off the net, drop shot them. It's very difficult to lob a ball that you are running forward to get.
Another example...your opponent is pouching frequently and cutting off your return, hit the return down the line, right at them, or lob them.
If you don't feel comfortable hitting some shots, you can mix it up anyway. Vary the height of your shots, alter your spin, come to net, take a high ball out of the air, or change the pace.
Mix it up and do something out of the ordinary and you'll surprise your opponent and keep him off balance.