1. Playing Too Many Hands
An early lesson in poker is to realize the majority of hands you are dealt must be folded. I’ve known an amateur player turn round to me and say You’ve got to play the hand you are dealt, why fold. I was shocked and soon put them right. However, there are a lot of beginners that seem to ignore this most basic rule.
They will call with ace-rag out of position, even call a raise with it, they play any two suited cards or even any picture card. You can get away with playing loose like this in a game of no limit hold em but you must have a strong post-flop ability to be able to pull it off.
Situation dependent, most of the time you are looking to only play premium hands such as high pocket pairs, and very strong aces. Simply fold the rest.
2. Not Folding Mediocre Hands
After the flop has hit, amateur players find it very difficult to let go of marginal hands. Suppose they hit middle pair or top pair with top kicker, the will find it hard to lay down. Its a crazy situation to still be involved in a pot holding top pair when there are flush and straight draws on the board and players are betting like theres no tomorrow. I’ve seen people play online when they will see their hole cards all the way to the river even though the board has paired up, AND there is 4-to-a-flush on the board, AND a straight possibility. They just wouldn’t let go of their flopped top pair.
The best hand on the flop may not always be the best hand on the river. Play with caution and don’t be afraid to get out if the action heats up and you are holding a marginal hand.
A good way to look at it is to look at the board and think to yourself “What two cards could my opponent be holding for them to beat me?”. If you can narrow it down to one or at most two sets of hole cards you should be fairly confident in carrying on playing. If you have to say to yourself “I hope he doesn’t have X, or Y, or Z, or A, or B or C…” then you should really think about folding. The more combinations of cards that your opponent could be holding that beat your hand, then the more likely it is they are holding one of them. If there is only one or possibly two combinations of cards that beat you then continue to play but with caution. Bet out or raise to gain information on how good your hand is. If they fold, you win the pot, if you are raised then you are probably beat.