Telltale Poker Tells: 2
There is a common tell for bluffing as well. More often than not, a player who is bluffing may try to stare you right down because he wants to intimidate you. The reason for this, of course, is because he is attempting to pull off a bluff. If your hand is a strong one, take the opportunity to call; if it is fantastic, start raising.
The eyes of poker players may or may not be the windows to the soul, but they are definitely the windows to motives. If a player sneaks a quick peek at his chips, he likely has a strong hand.
Online, as mentioned, there are tells as well. A lot of tells involve the time it takes a player to make a move. For example, during a limit game, duration is everything. A quick call when there are two straight or flush cards showing, it may mean a draw.
Players who take forever to think and who seem like bad players are probably thinking about whether or not to call or to fold, indicating a weak hand.