If you are new to Holdem, you're bound to make mistakes. The following are five of the biggest mistakes that beginners make. Hopefully by understanding what they are, you will be able to prevent them from happening to your own game.
#1 – Playing too many hands. This one's not even close, it's easily the most common mistake that beginning players make. They don't understand position, how their opponents play, and the value of particular hands. For example, a beginning player looks down at an ace and thinks it's a great hand because, well, they have an ace. They don't care that their kicker is a 3 or that they are acting under the gun. They have an ace and want to play it.
#2 – Calling too much. This works hand in hand with #1, but a common tendency new players have in Holdem is calling too often. These players will call raises with marginal hands that have no business being in the hand or will call bets post-flop with hands like bottom pair or gutshot straight draws because they don't understand the value of those hands. In fact, while calling with bottom pair might often be the right play, beginners aren't making the call for the right reason, they are calling merely because they have a pair, not because they think their hand is best.
#3 – Betting too little. It is not surprising to see a new player make a bet of 100 into a 1,000 pot. Why? Because they don't understand the value of making larger bets and the problem with making a small bet. They believe that any bet is good enough, even if it is the minimum bet. They don't realize that bets of this nature can often give their opponent the right price to proceed with the hand or can make them seem weak and force them to face a raise in a situation they might not want to be raised.
#4 – Playing hands out of position. Another common problem beginners have is not understanding position and the value it has. It's one thing to raise with a hand like A-10 when you are first to act from the cutoff. It's a completely different thing to raise with a hand like A-10 in early position and call a re-raise from a late position player. If you can remember that the later in position you are, the wider selection of hands you can play and vice versa (the earlier position you are the fewer hands you should play), you'll save yourself a lot of chips over the long run.
#5 – Impatience. This happens in several ways. One, a player may not have been dealt a playable hand in a while and feel that they have to play a certain hand even though the betting/action indicates that they are way behind. Their impatience because of not playing ends up costing them money. Two, when a beginning player loses money they tend to get impatient and want to win it all back immediately so they'll start to take unnecessary risks and end up losing even more. Be patient, wait for the right situations, and your bankroll will be better off because you did.
The Main Holdem Strategy Index: The Great Game of Holdem