what do you watch?

the_main

what kind of tells do you look for while playing online?

or anything in general you look for to gain advantages over your online counterparts.

DJP

Since you can't see their faces, all you have left are their bets or calls, and how long it takes them to do either. It's more of a feeling than anything, but you base it on their play you've seen up to that point. And to a degree, the size of their bet/raise. Just pay attention to the bets after each card, and watch what they have after showing the hand. It will start to give you a feeling for what kinds of cards thay may bet with. It's not an exact science but..........

PS, you want to be doing this even in hands you're not playing in. Make notes if you have to.