The easiest way to catch bluffing players is by looking at their betting patterns over a series of hands. Remember the betting history and get as much information as possible, this help you make your moves in the game, gives you serious advantage when the game becomes heated, but also you'll need it to catch a person when they are bluffing. The more info on an players tendencies you have collected, the more chances you are to know when he is trying to make a bluff.
Pay special attention to your opponent’s reactions to the cards he gets, good or a bad hand - facial expression, body movements and how much is your opponent talking.
If heputs on a very strong confident face, probably he's trying to bluff you intothinking that he has a strong hand. However, if your opponent becomes passivethen probably he is trying to bluff you into thinking that he has a bad hand sothat you will stay in.
If a player’s demeanor pulls a complete change from any of the other hands that they have won, you can probably pretty safely say that they are trying to bluff you.
Be aware players who adopt fake poker face at the earlier part of the game and then use them to bluff you later on.