Determining what type of player your opponent is can help you make good decisions, most importantly, shot placement. If you have a group of people that you play with, it should be easy to recall the strengths and weaknesses of each. When playing against a new opponent, it should be your priority to determine what kind of player they are.
Aggressive or DefensiveEdit
This is the basic divide in table tennis players, and can usually be easily determined. There are many indicators of aggressiveness or defensiveness. Does your opponent seem to crowd the table even when shots are flying quickly? That's an aggressive stance and you can expect fast returns, which can go into the net or on your side. Defensive players tend to just get the ball back, waiting for their opponents to make mistakes. Defensive players tend to not slam balls, and some extremists refuse to slam even when there is almost no chance of missing. Good players can shift their style of play, just as no basketball team plays offense all the time. When a chronically defensive player and a chronically aggressive player play, the defensive player will find himself standing far from the table, returning the blazing shots the aggressive player is making. Either one could win, taking advantage of weaknesses (with shot placement) could win the game.
Forehand, Backhand, or BothEdit
This is pretty straightforward and easy to determine. Left-handed players can throw a wrench into the works, though. Simply, does your opponent use energy to favor forehand or backhand, or does he hit both with no real preference to either? If they favor one or the other, use shot placement to take advantage of their weaker side.