Have you ever studied your opponent to see exactly when in his strokes he commits to a specific placement? There really are two important points in the swing.

The first is when the opponent has committed to the placement, but you don't know where yet. Normally you would not react to this, but sometimes, against a predictable opponent (which means most players), you can anticipate. For example, if you serve a deep breaking serve to an opponent's backhand, most likely he'll return it to your backhand. So you might anticipate this, and at the instant when the opponent has committed his direction - but hasn't actually telegraphed the direction - you might anticipate his return by stepping over to attack with your forehand. Don't overdo this, but it's a definite tactical advantage if you can do this sometimes.

The second important point in the swing is when the opponent has telegraphed where his placement will be. You should learn to observe this so you can move the instant you can see the direction. Many players don't move until the opponent has hit the ball, but for the large majority of players, you can see where they are going by the time they start their forward swing. At the higher levels, many players learn to hide their direction longer and to even fake one way and go another, so against players like that learn when they have really committed.

The shoulders are often the giveaway for where a player is going on the forehand. Many players line their shoulders up early to hit crosscourt or down the line, and it's like they have a big sign across their shoulders saying where the shot is going. When you first learn the forehand, this is fine, but as you advance, learn a little subtlety and deception. For example, from the forehand side, rotate the shoulders way back as if you are going down the line, then at the last second whip about and go crosscourt. Or set up to go crosscourt, and at the last second rotate the shoulders back more so you can go down the line. Or simply cock your wrist back at the last second and go inside-out down the line. These are easier shown then explained - have a top player or coach show you how to do these shots.

There's a long history of players experimenting with how wide to keep their feet. There have been times where the trend was to keep the feet closer together, no more than shoulder width. However, that has pretty much died out. Suffice to say that if you watch videos of all the top players in the world, one thing that stands out is that just about all (I'd say all but I haven't had time to watch every single player) keep their feet rather wide. This gives them stability and balance when making shots, as well as lowering the center of gravity, which makes quick movements easier. There's a simple way to verify this, and see what the world-class players really do. Go to the ITTF world ranking list. Pick a player. Then go to youtube, paste the player's name in (and perhaps the words "table tennis" afterwards), and check the videos that come up. In general, the taller the player, the wider the stance, but even shorter players keep the feet wider than shoulder width. 

Many opponents push back deep any backspin serves, and will often even do so against a sidespin or even topspin serve by chopping down on the ball, often right off the bounce. And so you get a predictable backspin return off your serve.

If the opponent is going to give you these slow, predictable backspin returns, then you must take advantage of it. This means starting all of these rallies off with a serve and loop, either forehand or backhand. Simply decide you are going to do it, and do it. Yes, easier said than done, but the more you do it, the easier it becomes. You don't need a lot of speed as long as you get good spin, loop the ball deep on the table, and vary the placement to the wide backhand, wide forehand, and at the opponent's elbow.

Often it's best to serve short to the middle. By serving short, it makes it difficult for the receiver to attack the serve, and so you get those predictable long push returns. By serving to the middle, you cut off the extreme angles.

You should favor your stronger side - usually the forehand, though not always - but it's better to be able to attack from both wings when necessary than give away such a free attack. Don't over-anticipate the direction of the incoming push; wait and see the actual direction as a crafty opponent might aim one way and change directions at the last second.

How important is it to attack these long backspin receives? I've seen top players coach matches where they were literally confused that they had to actually tell a player to do this since it seemed so obvious and second-nature to them. 

If you have a tricky serve that opponents miss or pop up over and over, that's great. However, too much reliance on this can actually hold you back. The same tricky serve that your peers mess up against might be returned more easily by stronger players, including the ones you hope to learn to beat. For example, if you have a side-top serve that many opponents push back and so pop up, stronger players, especially after they see the serve a few times, might just drive or loop it, and suddenly your serve is a disadvantage. So instead of relying on winning off the tricky serve over and over, develop a good third-ball serve, one that players at nearly all levels will return somewhat passively, allowing you to attack. Then you can use the tricky serve as a highly effective variation that even stronger players might never adjust to.

Your typical third-ball serve is a short and low backspin or side-backspin, which is often pushed back, setting you up to loop (or in some cases, a regular drive). The irony is that if you do these serves well, opponents will tend to expect backspin, and so when you fake backspin but instead give side-top or no-spin (by contacting the ball near the base of the paddle but still exaggerating the serve motion), the opponent will often push and pop the ball up. Sometimes the no-spin becomes the main serve, with spin the variation, since no-spin serves are harder to push heavy or drop short than backspin, and if very low, are often harder to attack as well.

The key is that you have to *do something* when returning any long serve or you give the opponent a big opening. And that usually means attacking it. Against a long serve to the backhand, that usually means either backhand looping or hitting/punching a strong backhand. A player with good footwork may step around and loop with the forehand, but most can't do that on a regular basis unless they are very fast or they anticipate the serve. If the serve is fast, you can use the speed against the opponent with a punch block. If you have trouble attacking the serve, try shortening your stroke.

You want to place the ball, usually wide to the corners, or (if the opponent isn't looking to attack with the forehand) a strong shot to the elbow. Shots to the middle backhand or middle forehand put little pressure on the opponent, and are often ripped.

You want to hide the direction. For example, if you aim your backhand crosscourt to the wide backhand, then at the last second change and go to the wide forehand, you can catch an opponent off guard. If you aim to the wide forehand, many opponents will move to cover that, and then you can do a simple return to the backhand.

You want depth. Even a weak topspin ball that goes deep can be effective if it either has topspin or is to a wide angle. (However, you don't want to rely on this - a good player might still tee off on this.) Against some players who hang back to counterloop, a shorter, softer, spinnier topspin return is more effective, but don't overdo it or they'll get used to it.

A sudden chop, chop block, or sidespin block can also be effective, but only if you can control it, and usually only as a variation. If you can deaden the ball with a chop block or sidespin block, many opponents will have great difficulty. If the serve has sidespin, try sidespin blocking it back, using the opponent's own spin against him. (Go with the spin, not against it, i.e. against a forehand pendulum serve, your racket should go right to left for a backhand sidespin block.)

Lastly, variation is important. If your opponent knows what you are going to do, things get pretty easy for him. Even if you are going to loop all deep serves (as most advanced players should), you should vary the placement, depth, speed, and spin, and throw in sidespin loops as well.