There are two different types of bluff.

Small Bluff

The first I call a small bluff. This is a small bet into a small pot. You aren't really representing any particular hand, it's more that you are asking if anyone else has a hand. This includes bets into unraised pots from any position, or a continuation bet when you are the the preflop raiser. These should be attempted as often as possible.

Big Bluff

The other type of bluff is a big bluff. This is when your opponent has in some way signaled that he has a hand, and you try and take him off it despite this. These are much trickier and need to be approached carefully. There are a number of factors that need to be in place before attempting a big bluff.

•1.      Your opponents hand must not be that strong, relatively. So if you think your opponent has AA, then a flop is K25 is not the flop to take him off it. Try a flop of 567;

•2.      Your opponent must be capable of folding a strongish hand if he thinks he is beaten. There are a lot of players who simply hate to fold anything. Do not bluff these guys! Just wait for a good hand.

•3.      The hand you are representing should be clearly identifiable. A bluff has much more chance of success if there is a obvious hand like a flush that you can represent.

•4.      Your hand should make sense. Your line should be totally coherent, and the hand you represent should tie in with your actions on earlier streets. Opponents will take note and call you more lightly if your hand makes no sense.

You should be able to bet enough to make your opponent fold. It seems obvious, but make sure you have enough chips to make a bet to which it's possible for your opponent to fold. This means that the earlier in a hand the better it is to bluff; as your opponent has future bets to worry about.