Great poker players know when to bluff an opponent who shows weakness. Even greater poker players know when to call an opponent who is bluffing. How do you know when an opponent is bluffing and when he actually has a good hand? Picking off an opponent's bluff requires a good read on him. Your read on an opponent comes directly from observation of his past play. Pay attention to how he plays strong hands, how we plays weak hands, and any other physical tell that gives you a measure of the strength of his hand. By being very observant, you will notice patterns in the way your opponent plays his hands. An opponent who regularly checks his strong hands on the flop will probably be weak when he bets the flop. If you can recognize this betting pattern in your opponent's game, you will be able to call his bluff. Observe everything your opponent does when he plays in a hand and keep track of his tenders.
Force yourself to get into your opponent's head and think like him. How often will he bluff on the river when he misses his draw? What did your opponent do the last time he bluffed? If your opponent shows weakness or does something to indicate he has nothing, you should call his bluff. At first, you will be wrong and will lose some money calling down with the worst hand. Over time you will develop an instinct, an automatic ability to sense weakness. It takes a lot of time and focus to develop your instincts at the poker table. Play at a level where you can afford to lose the money. Push yourself to become a better player by trusting your readings and acting on them. Even if you only have ace high, trust your readings and call. Forget about how much money you are going to lose right now. In the long run, you stand to win a lot more money by calling down an opponent's bluff.