Picking up a tell - a hint that a player unknowingly gives that reveals the strength of his hand - often means the difference between winning and losing a big pot.

Most physical tells, however, are notoriously unreliable. What might signify a bluff from one player just might indicate a full house from another. That's why it's wrong to generalize physical tells by adhering to profound-sounding statements like, "When a player throws his chips in forcefully, it's a bluff." It's simply not true in all cases.

There are, however, some tells that are more reliable than others. One in particular is the habit of glancing at one's chip stack. It's powerful because so many players aren't even aware that they're doing it.

Let me explain. Some players will immediately glance at their chips as soon as the thought of making a bet crosses their mind. Say a player is holding pocket threes and another three hits on the flop. That player will often take a quick glance at his chip stack as soon as the flop is revealed. It's like hearing a voice inside your head saying, "Oh, three of a kind. Next step is to bet. Where are my chips?"

That's when you'll notice the quick glance. Once you find a player who has this habit, it will be the most reliable tell you will ever spot.

Now, a player with this tendency might also look at the flop with a blank stare, never once glancing at his chips. That is a tell, too. Since you know that he glances at his chips when he wants to bet, you can infer that when he doesn't, he has no intention of continuing with the hand. The pot is yours for the taking with a bet.

Here's an example of how picking up on this particular tell can help you avoid being trapped.