2. Not able to fold big pairs.
This is a mistake I see a lot of beginners make. I'm not suggesting that you should be automatically folding your big pair when an overcard comes on the flop but you need to be able to pick up on some of the obvious situations in which you are beat. Say we raise on the button with KK and we get 2 callers. The flop comes 810A (we all know an Ace hits the flop 90% of the time when we have Kings). There is a bet and a raise. You have to realize that 99% of the time your hand is no good here. Even with a bet and a call your KK is behind a large percentage of the time. It's as though people decide that because they have KK they are going to be going all in. My advice is at least wait until you see a flop before you make up your mind that you are going to be going all in. Improve your poker game.
Don't be a Poker Fish!