Checking Hole Cards after a Flop
If the flop reveals the opportunity of giving someone a straight or flush draw, observe people who are checking their hole cards several times. They’re probably checking to see if they have what it takes to benefit from the flop – whether that red Ace was a heart or a diamond. Remember that a player doesn’t have the straight or flush at the moment, because if they did, there would be no need to recheck their cards, but now he or she is checking if she has a draw to it.

Taking a Long Time before Calling a Bet
If a player stares at the pot and looks like he’s doing some calculating in his head, he most probably is doing so. He’s very likely to be counting the pot odds to check if it’s worth it to try and catch the cards are needed to complete his drawing hand.