Four Tells To Look For (Part of Turn Play):
1. Early Reachers
Some players reach for their chips prematurely. Give yourself a few extra seconds before making your play, and you may find out some free information. Of course, some players reach for chips to discourage you from betting.
2. Speed of Their Action
The time it takes an opponent to call a bet on the turn may reveal some patterns like
he is on a draw, or discouraging you to bet the river, or something else. You need to figure what the speed of the action is telling you.
3. Card Protectors
Identify a pattern based on whether where his card protect is being placed. For example, if he normally has the protector on the cards, and this time he doesn't, it may mean he isn't going to play. Again, you need to figure this out.
4. Quick Checkers
Quick checks on the turn may be that he is going to check-raise or he is on a draw. Again, each player is different so you need to figure it out.
Next: River Play
From the book: Daniel Negreanu's Power Hold'em Strategy