Poker is a game of chance and luck, but there is also an element of skill. A player can improve his chances of winning by making decisions that maximize the value of his strong hands and minimise losses when he has weaker ones. This is known as the min-max strategy.
To do this, a player must be in the right physical and mental state to play poker. This requires good health, proper sleep and diet. It also means taking regular breaks from the game. Those who are able to do this consistently will make more money than those who play without breaks or who are not in the right frame of mind for the game.
Another element of the game is being aware of your table image. A bad table image can lead to you being forced to call bets that have a negative expected value because other players think you have a strong hand. This can quickly eat into your bankroll, especially when you get caught in an ugly spot.
Finally, you must be able to read your opponent. There are a lot of different types of players in poker, from the recreational player who thinks nothing of losing money to the hard-core nit who hangs onto every chip for dear life. Reading your opponent allows you to put them on a range of hands, and only by putting them on a range can you hope to make the correct decision most of the time.