Lots of good advice posted but mine is and always will be about
bankroll management and tilt control. You need to be properly rolled for poker. My one friend is probably better at the game than me but I have been much more successful than him. The reason is he plays out of his bankroll. He has gone busto both live and online several times. I don't care how good you are; you will go through downswings. If you are not rolled properly you will go broke. Similarly, tilt will make you busto. I never get mad at the tables. I always keep a leveled head. I never get too high or too low. If you get unbalanced one way or another, you will lose. Another tilt advice, do not mock other players especially fish. They are what makes this game worth playing. We had a really juicy game at one of the
casinos going every Thursday. All of the guys were nice but also clueless. Of course, sometimes the clueless get lucky and win. One guy at the game was a sore loser and yelled at a couple of the players. Then, they stopped coming and the game got tougher to beat. they were having fun and losing money and not caring. then it was ruined by one guy. moral of the story: you need to be happy for them and not berate their play. They are what puts money in our pockets. Play nice and keep then coming.