Range

You are playing against a particular fellow you know pretty well. You've played him many times and you know he tends to go all-in right after the flop if he catches anything as good as top-pair with an ace kicker, or better. Obviously I am outlining an example here to illustrate a lesson, and it's rare that you will ever have an opponent that is this predictable, still most people tend to do the same things over time and their actions can lead you to make educated guesses as to what they are holding.

So, getting back to our example, you know the range of hands this fellow is likely to be holding should he go all-in after a flop, and knowing this you would be foolish to call on a draw or with top pair king kicker. But what if you have top two pair? Or bottom trips?

Knowing an opponents range makes the decision to call or fold one of probability: does the hand you have beat most hands in his range? Remember that he is more likely to be holding the hands at the low end of his range than those at the top - simply because the lower a hand rank, the more common it is. Still it might take a mind-boggling amount of math to figure out all the possible odds of the different hands he could be holding.

A simple rule I use is once I am satisfied I know an opponents' range, I set my own range of hands that I would call with somewhat higher. So if I only call the guy in the example with two-pair or better, I'm likely to win most of those showdowns.

If I think my opponents are experienced, I might play loose at first to get them to believe my range is much broader than it is. The truth is most players start out a session playing tight, but gradually lower their standards as they go along. It seems to be a natural movement. You should try doing the opposite, starting out loose and then tightening up as you go. The problem is that it is much harder to do than it is to say! Everyone starts out trying to play their best, only to loose discipline over time. Fight this urge!

Watch all hands very carefully, even those you are not involved in. Pay attention to what hands your adversaries think are good enough to bet big on. This will give you good idea of what you'll need to beat them.