Table Tennis, when played well, is an incredibly fast sport. Combine good racket speed, a $200 blade, and high tension rubber and you should have all the speed needed to score some pretty impressive points. Hitting a ball fast is something some players do better than others, but under the right circumstances, nearly every player can make a strong forehand drive or smash. Looping requires quite a bit more experience, but the speed of the shot often has more to do with proper technique than physical strength.
As a coach, I am surprised at how rarely I have ever had to tell players that they need to speed up some aspect of their game. On the other hand, very few sessions go by that I don’t have to urge someone to slow down. Typically, developing players scold themselves when a well-placed ball gets by them. Laziness, old age, and sluggishness are just some of the reasons I hear about when points are lost. Most of the time, the ball got past them because they were out of position and their previous shot had guaranteed that they would have trouble getting to the return. It turns out that being faster would not have helped nearly as much as being smarter.
When players hear that speed is an essential element of playing successfully, the interpretation is that faster is always better. In fact, some coaches may mean exactly that. Perhaps a better way to present the element of speed is to talk more about timing. A stroke that is too early is no better than one that is late.
The primary flaw I see with most intermediate level players is over-hitting and accelerating too soon on their looping strokes. To hit a ball at near full power, it is essential you be in perfect position to make such a strong shot. Starting a loop stroke too early or too fast quite often results in missing the ball entirely. The solution to both of these problems is slowing down until you get the timing right. It may seem odd that the way to learn to hit the ball faster is to do more footwork drills. As you gain confidence from being in the right position, stronger shots will naturally follow. Even under the best circumstances, I never recommend that a ball be hit any faster than 90% of maximum speed.
The timing of a loop can be a bit more fluid than drives, since the ball can be stroked after the top of the bounce. This actually gives you even more time and less reason to rush. If your loops are very inconsistent, it could be helpful to begin practicing loops at varying speeds. You might be surprised to find that when you slow down some of your shots, your strong shots start landing much more often.
Take a good look at the best players. Of course they are moving very fast, but they rarely look rushed. Studying the changes in speed of players who play a similar style to you may be helpful. Different players and different styles have differing tempos. The footwork and the tempo of play is very different depending on how close to the table you are. Your playing tempo will also change depending on the type of opponent you are playing. Control of speed, not just speed, may be the key to your improvement because in this sport, timing is everything.