3. Heavy backspin:
When you're forced to hit a shot that won't have any power or land very far from your opponent, you can still make your opponent miss by making the shot sufficiently unpredictable. If you're not hitting hard, it's pretty easy to hit a backspin so heavy that the ball nearly bounces straight up instead of continuing forward. The result will often be a major timing and positioning error from your opponent. He'll tend to swing too early and also have to reach too far forward. This usually makes him hit long if he connects with any power, or it will throw him off so much that he'll barely connect at all.
4. Extreme slice serve:
This serve has the same effects as the true slice backhand, but for many players, it's easier to execute, because serves are the one shot on which you have complete control of the ball. It's also easier to hit an extreme angle with this serve than with most backhands. You can pull your opponent completely off the court with a well-placed extreme slice serve out wide, or you can curve the ball into her body. The "jamming" serve works especially well against tall opponents. This serve doesn't have much pace on it, so the receiver tends to think of it as "easy" when it can be anything but. Learn the extreme slice serve here.
5. High lob:
Some opponents will be too smart for this one, but most will fall for it. When your opponent is at the net, and you just barely get to the ball, try throwing up a lob around 35 feet high. If you hit your lob nice and deep, you're right back in the point, but even if it ends up shorter than you hoped, you might still luck out. Many players forget how hard it is to time an overhead when the ball is accelerating downward from a significant height, and even when they remember, the temptation, mixed with a little overconfidence, is irresistible. They try to hit your lob before it bounces, mis-time it, and hand you the point. 35 feet is about the right height not to be obviously too high to hit before the bounce. If you're way out of position, you might want to lob higher to buy more time, and although it's more likely your opponent will let the ball bounce, you might discover that his bounced overhead is another shot to add to your list of those he hates to hit.

