Bluffing 101

"You can fool some of the people all the time, and all of the people some of the time, but you cannot fool all of the people all the time." - Abraham Lincoln
One element of poker is deception. Bluffing is the quintessential trick in poker. Of course, the reasoning for a bluff is to deceive the other players into thinking you have a better hand when you actually do not. For a bluff to work, you need the other players to think you actually have that better hand. Many beginning poker players love this idea of bluffing and often misuse it. The value of the bluff increases under certain general circumstances that often have a lot to do with information you assume about the other players. This vagueness makes it difficult to give definitive reasons or places to bluff. Some less generalized times to bluff and some advice are given below. The bottom of the page gives some more ideas and perspectives on deception in poker.
Some typical reasons to bluff...
A. When there aren't many other players in a pot.
Simply put, it's easier to trick a couple people than a crowd. With fewer hands out there, chances are better that no one has made a reasonable hand. This is fairly common though, so many players won't believe you. Some will stay in the hand just to "keep you honest", so sometimes this needs to be a persistent bluff over a period of two or three betting rounds. That can be costly if they don't fall for it. You need to know the players before you use this type of bluff.
B. When you're up against fairly tight players.
Those that tend to fold easily are the biggest targets of a bluff. Bets will be put out just as a form of information gathering on this player's hand. If you bluff early (pre-flop, flop) against a very tight player and they don't buckle, you should think twice about trying it again on a future round. They have something. Your job is to determine whether they have a made or drawing hand. Once again, you need to know the players.
C. On the river.
Especially if apparent drawing hands missed. That's when players react to rule #1 "the moment you know you can't win, throw in your cards". It is often a good idea to bluff with a weak hand, like ace-high or lowest pair with these kinds of bluffs, because some players will stay in just because of pot odds. If you do that, it is actually semi-bluffing (see the bottom of the page).
D. You're in late position and everyone else checked.
This one you'll have to gauge for yourself. It will most likely force some players out, but not all. This is a pretty common bluff once again, and many players will stay in just because of bet odds, and/or to once again "keep you honest". This is another example of a bluff that needs to be more persistent over a couple betting rounds.
E. You bet pre-flop and missed.
That's because they don't know you missed! This can be dangerous, and you really have to evaluate to board before you get into this one. Sometimes it's good to bluff when AK misses, sometimes when 99 misses. You have to really feel this one out.
F. You have given other players "the fear".
It's about how other players perceive you. If you just won a hand through good play, the players who say "nice hand" are the ones who now respect you. They will more likely fold to your bluff if you play it right. The trick is to play the hand exactly the same way you played the other winning hand. Give it the "here we go again" act.
G. When the flop isn't so great.
Some players will fold automatically if all they have is an overcard. With a rainbow flop of 2, 6, 9, not many players will have much. This is another example of a bluff that can go horribly awry. I wouldn't be too persistent in this case, unless only more low cards pop up. Once again, know your players.
H. Pre-flop on the button, and everyone else has folded.
This is usually best used with tight players to your left. Its good because it can change from a bluff to a deceptively good hand with luck and the right flop.
I. When there is a pair on the board.
This is especially useful when the pair is 88 or lower. Chances are that these cards might have been folded or are still in the deck. This is one situation where you want to evaluate the hand very carefully if they do call though. This is a great situation to read the tells of the players who are NOT involved in the game. It's much easier to give away the fact that you HAD a card than if you HAVE it.
Keep in mind that these are pretty common reasons to bluff. Many players know these reasons. Most of the time it just won't work. The main thing is always to know your players and to not do it so often that it never works.There's some great books about bluffing out there. We suggest reading as much as you can about it, as it's one of the most misunderstood aspects of poker.
Other bluffing topics...