Read the Opponent’s Spin
All high-balls should not be smashed in the same manner.  When you see a high topspin ball, step back slightly, start your racket high, and smash forward and down.  When you see a high backspin ball, step forward, start your racket lower and the angle more open, while smashing forward and slightly up.
 
Add Spin to Your Smash
A smash with some topspin will possibly be 10% slower, but it will usually have about 50% more control.  Be consistent in smashing – add topspin!
 
Place Your Smash Correctly

When hitting backhands, many table tennis players do a great job hitting to different locations.  Because they are able to bend at the wrist, these players are easily able to contact the inside of the ball, the back of the ball, and the outside of the ball in order to hit to different locations.

There is 1 shot in table tennis that will really hurt you.  But before I tell you what the shot is, I’ll first make a couple of observations about your body positioning.
 
If you attack with your forehand from your forehand side, it doesn’t really matter where you attack.  You should mix up your placement – wide forehand, wide backhand, and middle transition.  Because your body is centrally located in relation to the table, you will likely be able to recover quickly for the next ball.
 

The Fastest Way to Improve
 
     If you would like to improve your game 50-100 points in the near future, focus on improving your ball placement.  To make stroke changes, it takes persistent coaching over an extended period of time.  However, if you can take the strokes that you currently have and improve your placement, then you should see instant progress.