Server seeing is probably the most difficult part of the sport. You absolutely must understand the spin. There are clues you need to look for when reading spin. First, and most important is the server's contact. If you can see the direction in which the table tennis racket was traveling at contact, you have a good chance of knowing what spin it is. If the racket is moving downward behind the ball or forward under it, it's under spin.
If it is moving up on the back of the ball, it would be top spin. Any sideways motion will impart an additional side spin component so it could be side under or side top spin. Second, look at the trajectory. Generally, a top spin ball [arcs 00:56] move quickly and if the ball floats, it's probably under spin. As a last resort, look at the print on the ping pong ball. If it's low to medium spin, our eyes can pick up the spin direction.
Watch how [Luffy 01:19] changes his wrist angle at the last moment to change the direction. The turning surge very much depends on experience. Recognize the spin and if you missed anyway, you'll know what adjustments to make next time.