When learning a new serve, focus exclusively on developing maximum spin with your wrist.
 
When smashing topspin, step back away from the table, while smashing forward and slightly down.  When smashing backspin, step close to the table, which smashing forward and slightly up.
 
Remember to anticipate with your feet, while keeping your racket in-front for last second adjustments.
 
When blocking, remember to think about ball control, placement, and extending the rally as long as possible.