How do you know what spin is on the ball, when the opponent serves and what is the best shot to return them?
It’s really important to watch your opponent very closely when he/she serves. More specifically you need to watch your opponent’s bat when it contacts the ball.
As a general rule, if the bat is moving down when it contacts the ball, it is likely to be a backspin serve. If the bat is moving up when it contacts the ball, it is likely to be a topspin serve.
Here’s a video I made about how to read service spin, which explains this in more detail: How to read service spin
If the serve is backspin or sidespin with backspin, the easiest way to return is with a push. Other options would be a flick (if the serve is short) or a loop (if the serve is long).
If the serve is topspin or sidespin with topspin, the easiest way to return is with a block or a drive. Other options would be to flick (if the serve is short) or topspin (if the serve is long).
Returning serves is usually the hardest part of table tennis for most players. Reading the spin is an essential skill and you should start with this. Then you need to find a way to return serves which suits your playing style. Any of the options I mention here could work – push, loop, block, drive, topspin. Experiment with different options and see what works for you. Good luck!