if your reffering to watching players online, its obviously harder than face-to-face. playing online, (absolute) I came aware of the players who join all the tourneys that I played. Usually when I wanted to know what the guy had I would follow his bet to the end. Yea you lose, but you can learn alot. What he bets before the flop. He his betting changes when he sees the flop and so on. Usually its trial and error. Not the best advice but it works in the long run. Also, look to what they bet in what position. Usually the BB will call and duel it out. Or you can just sit and wait to see his cards, eventually you'll see people's cards by them playing, so patience is a good thing to have. hope this helped a little, if not let me know, I'll try to clarify it.