Poker is a card game where players place chips in the pot before betting on their hand. It is not as simple as putting your cards down and hoping for the best – it requires skill, psychology, and some luck. It also requires the ability to bluff – a good bluff can win the whole pot.

In poker and in life, it is important to understand how decisions are made under uncertainty. You must be able to estimate the probabilities of different scenarios that may occur and then determine which ones are most likely to happen. For example, you need to be able to decide whether to raise or call a bet when you have a weak hand versus a strong one. This type of decision making under uncertainty is very similar to deciding under risk in investing or a business venture.

In addition to observing betting patterns, you should also pay attention to the size of your opponents’ chip stacks. If a player is short-stacked, it will be easier for you to bluff against him. In addition, a player with a small chip stack is more prone to fold than someone with a large stack, as they don’t want to bet too much. Observing body language is also helpful. Classic tells include shallow breathing, sighing, nostril flaring, eye blinking and excessive swallowing. These are signs that your opponent is trying to disguise a weakness in his or her hand and is probably bluffing.