Lots of short balls are also off-speed, so if you look to tee off on those for clean winners too much, it's easy to spray them into the donation tray for your opponent's point fund. That short ball is your opportunity to control the action and put the other guy in a box.
If you can hit into an angle and put 'em on the run, that's always nice, but it's not always easy to do it. If you don't know how to hit a slice approach, it's time. That's the shot that gives opponents no more than a low skidder, forces them to hit up, and if you've planned ahead, you've moved in and are ready to volley to daylight.
Here's the catch: the best approach shots are often ones that land nice and deep. Place that ball only a couple feet inside the baseline and opponents are usually neutralized. Leave it short and/or sitting up and you're going to be the one playing defense.
Another great attack with that slice approach can be leaving it semi-short (not quite a drop shot) so that it forces opponents to lunge forward and shovel the ball up. Step up (yes, to the net) and enjoy your free lunch! This is the "north-south" sort of attack that's worth considering in case you can't beat someone with more of an "east-west" array of shots.