Staring Down Other PlayersIf an opponent is staring you down, he’s trying to represent strength. Usually though, he has a weak hand – he might have something, but it’s something that can be beaten or drawn out on.W
Holding BreathOften, inexperienced players will hold their breath if they are bluffing.W
Acting Uninterested in a Hand While Still in ItThis is usually a sign of a strong hand. The player is pretending that he’s not excited about his cards – but he is.S
Shaking Hands (nervous hands)During a hand, if you notice a player’s hands are shaking as she places her bet, she probably has gotten a really, really good hand. Perhaps the nuts.S
Rapid BreathingSome players can control the shakes, but it's harder to control the automatic heart-racing that comes when you see pocket aces or hit the flop really hard. If you can see a player's chest visibly rising and falling, they have an excellent handS
Sighing and ShruggingIf a player makes a show of sighing or shrugging, and says things like “Oh, I guess I’ll call,” or even “Why am I calling?” he probably is overacting and is trying to hide a big hand.S
Glancing at Chips After Looking at Hole CardsWhen a player looks down and sees strong hole or pocket cards, she may glance over at her chips to see just how much she can bet.S
Checking Hole Cards After a FlopIf the flop shows the possibility of giving someone a flush or straight draw, watch for people re-checking their hole cards. They’re checking to see if they have a piece of it – whether that black Ace was a spade or a club. The player doesn’t have the flush or straight at that point, because if they did, they wouldn’t have to check, but she is seeing if she has a draw to it.N
Taking a Long Time Before Calling a BetIf a player looks into the pot and seems to be doing some calculating in his head, he probably is. He’s most likely figuring out the pot odds to see if it’s worth it to try and catch the cards he needs to complete his drawing hand.N
The Rant

Many online poker tells are the result of bad players telling you that they are about to play even worse than normal. How nice of them. The most obvious of these announcements is The Rant. Flawed players go on tilt in all sorts of poker games, and online is no exception. The thing about online is loudmouths and bullies can't glare at, roll their eyes or do some other belittling physical action. But via the chatbox they CAN insult their opponents. They can't say "change the deck" but they can rant about software being rigged against their genius-level play.

Boiling it down to the basics, a player who goes on a rant about stupid opponents or rigged software might just as well paint themselves purple with ten inch letters: "I am on tilt". Besides obviously horrible opponents, ranters are THE players to target in any game, even more so than obvious multi-tablers. You want to play against people on tilt, but you also want to be sure you don't take them off tilt by playing a weak hand at them that helps them to calm down. Go ahead and goad abusive players in the chatbox. These are almost always players who think they are far better than they are, and play considerably worse when losing than when winning. They will often make the game. Treasure the ranters. To a large degree, winning poker is about defeating people who act stupidly. Ranters are at the top of the list.

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Chat revokedWhile not a subset of the rant, a small number of online players list "chat revoked" or something similar as their location due to the cardroom blocking their chat privileges for some prior immature or rude chat outburst. When you see one of these players who needs to tell you that their chat is revoked, you know you are dealing with an immature person. They are also more likely to tilt (though not necessarily, they could have had chat revoked for racist or misogynist talk). If most chat revoked players lose a pot in an ugly way, you KNOW they wish they could call their opponent an idiot or worse. The WANT to rant. They WANT to insult. They want to exacerbate the tilt impulses they are feeling. You can even push them further by saying something like "nice hand" to the winner. You should be able to see the steam coming out of the chat revoked player's icon.
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Watch the EyesThis is why many pros wear sunglasses or visors/caps when playing, they know that the eyes rarely lie. For example, many players can't help but stare at big hole cards, so their length of time peeking is longer. Conversely, if a player is looking to steal the pot, he may look to his left to see if the remaining players, who haven't yet acted, have quickly glanced at their cards and are likely to fold. Another example, a player may try to ask you questions about your hand, knowing that people rarely can "look someone straight in the eyes" while being dishonest.U
Facial ExpressionMany pros try to disguise their entire face by wearing a cap and looking downward. This is to avoid the classic stare-down that poker pros are famous for. They may try to study your face for nervousness (detecting a weak hand), or even look for repetitive characteristics like a body "tic". You may have obvious unhappiness in your face when your hand is weak, and conversely, you may show a contrasting show of confidence when your hand is strong.U
Weak is Strong or Strong is WeakIn its most simplistic form, this usually applies to novice players but frequently applies to pros as well. Basically, players like to be actors, and when they have a monster hand they tend to look disinterested. For example: "Oh, is it my turn to act" or "Oh I guess I will play these cards". Alternatively, a player increasing the level of his voice while raising the pot, and trying to look intimidating.. may be running a bluff.U
AnxietyAnxiety typically occurs in people when they are confronted, or anticipating confrontation. Psychologists call this the "Fight or Flight" stimulus response, which links back to the days when we were cavemen/cavewomen. Physical changes happen including flexing of muscles, eye pupil dilation, palpitating heart rate, dry throat. In poker, when someone has a big hand they are typically ready for confrontation and can exhibit some of these characteristics. You may see the chest expanding abnormally, or you may notice the players voice become slightly higher as he makes a comment. Some of the top players in the game will stare at the vein on the top-side of your face for blood pressure changes. During a bluff, the player may demonstrate anxiety, but if he knows he will fold the hand if re-raised (non-confrontational end) may look quite comfortable.U
Glance at ChipsAgain, relating to the eyes. It is common for players to quickly glance at their chips if they connect with the board after a Flop. This may be a subconscious reaction, but the tell is the player is already planning his attack!
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Peeking Hole Cards on FlopSome players will take another look at their hole cards when, for example, the board is showing a potential 3 card flush draw. Typically, the player is looking to see if one of his cards is connecting, because he remembers only that the two cards are different suits.U
Repetitive Betting PatternsUsually the most revealing poker tells are based on the way a player habitually bets during particular situations. For example, maybe the player always checks when he has made the nuts, or a player may regularly fold after being re-raised.U
Body Posture and AttitudeSome players show obvious changes in their posture based on their attitude/hand strength. For instance, you may notice their shoulders drop/slump when they are not confident (weak hand). Conversely, you may notice the player is very attentive and sitting in an erect position when he has strength. You may also notice that a player who bluffs a lot, leans forward in a confrontational way... remember Strong is Weak!U
Chip StackingWhen you first sit down at a table, study the way the players stack their chips. Although it is a generalization, loose aggressive players typically maintain unorganized/sloppy stacks, while tight conservative players keep well organized/neat stacks.U
The GloatWhile not universally true, players who like to gloat after winning a pot are normally significant, longterm, weak-tight losers. Someone who regularly wins doesn't need to draw attention to that fact. Someone who is seldom a significant winner and needs to draw attention to that fact will be insecure as well as weak-playing. Gloaters are much easier to bluff after they begin to gloat, because they hate to now seem like a loser. They don't mind folding on the flop, or on the turn when an overcard hits, because they can pretend they got sucked out on. What they hate to do is be beaten on the river by an opponent with a superior hand. Gloaters can go on mega-tilt if they start losing after gloating, but more often they tighten up and enjoy their moment. They don't get them very often.U
The WhinerChatbox-whining players are different than the above. People who whine in public, to a group of strangers who couldn't care less, are very likely used to whining. In other words, a whiner is not likely to be on tilt when losing. A variation of The Whiner is he who whines "let's play head-up" any time someone beats him two hands in a row, or three of so ugly hands in an hour. Both these types are serious, long-term losers.U
The Rocket ScientistAny player who sees fit to lecture about how to play, and then is blatantly wrong, is a short term target. These players almost never last very long, are often first-timers and are seldom exploitable over time.U