The problem with playing lefties is two-fold: first, their shots come out differently than righties, and second, your natural ball placement to a righty is usually wrong against a lefty. The first part is more or less a matter of playing lefties until you get used to how their shots come out. The two shots from a lefty that most commonly mess up a righty are aggressive crosscourt backhands to the wide forehand, and their serves, especially forehand serves into your forehand that break away. (Hint - if you wait until the last second and then lunge for the ball as it breaks away, you're probably going to miss. Since you probably lower your racket as you lunge, you will probably go long.) It's just a matter of getting used to these shots.

One trick for returning a lefty's forehand serve into your forehand is to aim the ball down the line to the lefty's forehand. The lefty has to be ready to cover that shot, and so at the last minute you can take the ball crosscourt into their backhand. (This is assuming they are stronger on the forehand; if the reverse, you may do the reverse.)

Assuming you are comfortable against a lefty's shots, then the key becomes tactical. Where do you want to play your shots? For example, against a righty, you might play steady shots to the backhand, knowing the opponent can't put his backhand through you - but now that same shot goes into a lefty's forehand, where he may have more power. Or you might play quick shots to a righty's forehand, if your backhand is quicker than the opponent's forehand - but now that shot goes into a lefty's backhand, which not only may be as quick or quicker than your backhand, but also gives him that wide angle into your forehand.

So you may want to rethink your basic ball placement shots - but also use the reverse. Against a lefty, now you can hit quick, aggressive backhands crosscourt into their wide forehand; now you can lock them up on their backhands with your forehand into their backhand. Plus now you can use your own forehand pendulum serve that breaks into their forehand. (Though here the lefty has an advantage - he's probably more used to a righty doing that to him than you are used to a lefty doing it to you.)

So there are really three basic keys to playing a lefty - the aforementioned getting used to their shots and ball placement. However, the latter is really two things - learning (instinctively) what shots you do against righties that you don't want to do against lefties, and learning (also instinctively) what shots you normally don't do against righties that work against lefties. 

Many players have jerky strokes that make them look like a marionette on a vibrating bed. Jerky strokes mean the player is mostly using one muscle for the stroke, often at near full-power, which is nearly impossible to control. It's better to use more muscles smoothly, i.e. at less than full power, for control as well as more power since you are both using more muscles and are smoothly accelerating into the ball rather than trying to jerk your stroke at full power at the last second.

Jerkyitis is a horrible disease, according to top-secret papers from the Center for Disease Control. It cannot be cured. Like an accent a person has when learning a language at an older age, there will always be a bit of stiffness in your shots. But it can be controlled, just as that person with an accent can still develop conversational skills. How do you learn to control your jerkiness? By not rushing your shots, by relaxing your arm, and not trying to consciously guide your shots during a rally.

To avoid rushing your shots, you may need to take a quarter- or half-step back to give yourself more time to take a more relaxed shot. Players who suffer from jerkyitis often are jammed at the table, taking every ball right off the bounce, and doing so only grudgingly since they look like they to want to take the ball before the bounce. This is actually okay for a mostly blocking style, but for most shots, it's a symptom of jerkyitis; left untreated, your game may die a slow, malingering death.

Relaxing the arm is easy - you just need to do so. Before the rally, relax your arm at your side, then gently and smoothly raise it into your ready position. Okay, it sounds easy, and it should be easy, but the key is to keep it relaxed once the rally begins. There's a natural tendency to tighten the muscles as the ball is coming toward you as you try to guide the shot. Instead, just let the shot happen on its own - rely on your many years (months? weeks? days?) of training rather than trying to consciously trying to control each shot - which is the third thing you need to avoid to get rid of those jerky shots.

One way to practice smoothness is to do random drills. This means your partner or coach hits balls randomly to your side of the table, and you just react to each shot, using the principles outlined above. (You can do this either live or with multiball.) At first, have your partner or coach hit the ball randomly either to your forehand or backhand; when you can react to those shots easily and smoothly, then increase the complexity and have the shots go truly random, i.e. to the middle and wide corners.

We'll never wipe out jerkyitis, but if we all work together, we can wipe out much of its effects, and turn your game into an (almost) smooth-stroking table tennis machine. (In the interest of transparency, I am a lifelong sufferer of jerkyitis, but it hasn't stopped me from reaching a rather high level as a player and coach.) 

Many players develop a small but effective set of serves, and find success with this. However, often they are limiting themselves with a lack of variety.

While it is important to develop a small set of highly effective serves that you can use over and over, it's also important to have enough variety in your serves that you can most likely find one that the opponent has trouble with.

For example, many players develop very nice forehand pendulum serves, the most popular serve in high-level table tennis. But since so many players do this serve, many opponents are good at receiving them, while having trouble with other serves. I've seen many players who have trouble with a specific serve, such as a backhand serve short to the forehand. (This has the opposite sidespin as a forehand pendulum serve, though it can be mimicked with a reverse forehand pendulum serve.) And then when I coach against this player, I find that the player I'm coaching can't do this serve! Often they can do the regular forehand pendulum serve short to the forehand, but it's the other type of sidespin that the player has trouble with.  

Another example would be fast and deep serves. Many players have difficulty with certain types of these, such as fast and dead to the middle (elbow). And yet many players can't do this simple serve, and so are giving away many points, games, and possibly a winnable match. Fast sidespins to the wide backhand give many players trouble, and yet few bother to learn these serves. And then there are the all-out forehand loopers who loop every deep serve to the backhand - and woe be the server who can't cross up this player with a fast serve down the line to the forehand!

The list goes on and on, and yet the principle is simple. Learn to serve short and long (including fast) to all parts of the table with all varieties of topspin, sidespin, and backspin (and don't forget corkscrewspin and no-spin! See article on spin if you're not sure about these two), and you'll have it all covered. While you don't need to be an expert on every serve, you should be at least proficient at most serves so you can pull out the needed ones when needed.

If you are a looper - and that means most players from the intermediate level on - then when someone pushes to you and you want to loop, you should be in one of four mental states. We're assuming you can loop both forehand and backhand, or (if no backhand loop) have very fast feet for #4.

1) Loop forehand or backhand, depending on where the push goes. This means there's essentially a line from your opponent to your playing elbow (mid-point between your forehand and backhand), and if the ball is on the forehand side of that line, you forehand loop; if on the backhand side, you backhand loop.

Advantages: You are ready to loop anything, and you don't have to go out of position.

Disadvantages: Your opponent chooses if you are going to loop forehand or backhand (and presumably will have you do your weaker shot), and you might have problems deciding which way to go on pushes to the middle, especially quick ones.

2) Favor forehand, but ready to loop backhand if it's a strong push to the backhand.This means you are ready to forehand loop most pushes, including ones to the middle and weak ones, but won't force it against a good push to the backhand, which you'll backhand loop. (Of course some might just push this ball.)

Advantages: You are ready to forehand loop - presumably your stronger side if you choose this strategy - against most pushes, both strong ones anywhere except to the backhand, and weak ones anywhere.

Disadvantages: You may have a lot of ground to cover on some shots if it's a good push toward the middle. If you are ready to forehand loop and are forced to backhand loop, may not be ready and so may backhand loop weakly or inconsistently.

3) Favor backhand, but ready to loop forehand if the push goes to the forehand side.This means you are literally setting up to backhand loop most pushes, including pushes to the middle or even slightly toward the forehand side, but are ready to rotate the shoulders to the forehand side to forehand loop if the push goes there. You are basically telling your opponent, "I'm going to backhand loop, but if you want to give me an easy forehand loop, then push to my forehand."

Advantages: Allows you to really prepare for your backhand loop, often compensating for having less power on that side. Also allows you to have less ground to cover for forehand loops. Allows you to stay in position for most loops. If your backhand loop is stronger than your forehand loop, then allows you to maximize the chances of backhand looping.

Disadvantages: You'll be doing a lot of backhand loops, often weaker than the forehand loop. Can be caught off guard with a quick push to the forehand side if you are too quick to set up for a backhand loop. Can have trouble backhand looping pushes that go to the middle if you don't learn to step into position properly for this.

4) All-out forehand looping. You basically decide in advance that if it's humanly possible, you are going to loop with your forehand. Can only do this if your footwork is fast and technically good. Off the serve, good footwork technique and anticipation can make up for not having fast feet. (Note that the logical alternative to this, all-out backhand looping from all over the table, is rarely done since there's less range on the backhand side. There are some players who do this, but they are rare.)

Advantages: You get to use your forehand loop, presumably your stronger shot. Allows you to get into forehand position so you can do a series of forehand loops in a row. Takes the indecision out of the shot since you know what you are going to do.

Disadvantages: You have a lot of ground to cover, and so can get caught out of position, both while trying to make the shot and for the next shot. May make weak or inconsistent shots if you aren't in position quickly enough.

Conclusion: Which of the above do you use?

Where should you put your putaway shots? Whether they are smashes or loop kills, there are basically three options.

Option One: The easiest spot. This usually would be the longest diagonal. This gives the most table to aim for, and so is the safest and most consistent. The down side - it's also the spot most opponents will expect you to aim for, and so is the most likely to be returned. At the beginning/intermediate level, you should aim most putaways to the safest spot since it's probably not coming back.

Option Two: Aim one way, go the other. Most often this means aiming for the longest diagonal, and then, as the opponent moves to cover that spot, going the other way, usually down the line. This is riskier as you both have less table to go for and you are setting up to go one way, then have to change at the last second, but it's also going to make it very difficult for the opponent to return this shot. It's only at the higher levels that opponents can react and cover both corners.

Option Three: The opponent's middle. This is the transition spot between forehand and backhand. At all levels this is probably the most difficult spot to react to. There are players who can almost relentlessly return shot after shot at the corners, but go at their middle and they fall apart. This is the most common spot top players aim at. The down side - it means you don't get the long diagonal to aim for, plus it's a moving target, depending on where the opponent is. Also, a forehand-oriented player may counter-attack that ball with his forehand - but if he does, he's probably moving early, and leaving his wide forehand open, which is where you would go in this case.