A Summary of Poker Tells by Mike Caro

Players are either acting or they aren't. If they are acting, then decide what they want you to do and disappoint them.
Players often stack chips in a manner directly indicative of their style of play. Conservative means conservative; sloppy means sloppy.
Players often buy chips in a manner directly indicative of their style of play. Flamboyant means flamboyant; guarded means guarded.
Any unsophisticated player who bets, then shares his hand while awaiting a call, is unlikely to be bluffing.
A trembling bet is a force to be feared.
In the absence of indications to the contrary, call any bettor whose hand covers his mouth.
A genuine smile usually means a genuine hand; a forced smile is a bluff.
The friendlier a bettor is, the more apt he is to be bluffing.
A player glances secretly at his chips only when he's considering a bet — and almost always because he's helped his hand.
If a player looks and then checks instantly, it's unlikely that he improved his hand.
If a player looks and then bets instantly, it's unlikely that he's bluffing.
Disappoint any player who, by acting weak, is seeking your call.
Disappoint any player who, by acting strong, is hoping you'll pass.
Players staring at you are usually less of a threat than players staring away.
Players staring at their cards are usually weak.
Players reaching for their chips out of turn are usually weak.
A weak player who gathers a pot prematurely is usually bluffing.
When a player acts to spread his hand prematurely, it's usually because he s bluffing.
If a player bets and then looks back at his hand as you reach for your chips, he s probably bluffing.
A forceful or exaggerated bet usually means weakness.
A gentle bet usually means strength.
When in doubt, sit behind the money.
When tells conflict, the player is acting. Determine what he's trying to make you do by his most blatant mannerism. Then generally do the opposite.
A misdirected bet is almost always a bluff.