There are five rules to help you in developing your Poker expertise. Thses rules can also be applied to other forms of gambling as well as to life generally. Learn them and enjoy and profit from the game.
The first rule is to recognize that many people are making a living from playing poker. They are not relying on luck but on skill and intelligence. Therefore do not assume that you will lose or win based on luck. Luck has only a small portion to do with it. Any single hand will have luck as the major contributor but by knowing what you are doing and why, you will be able to turn the odds in your favor over the course of the whole game.
The second rule is to recognize that it is serious business. Therefore play when you are alert. If you are tired, you are giving your opponents an edge. If you are fighting a battle, you want to be fit and alert. This is a battle against opponents who want to take all of your money. If you are drinking while playing, you are giving your opponents an edge. If they are drinking, you might be taking away your edge which could turn the tide in your favor. Would the casino bring you free drinks if it was going to help your play? It's best to celebrate your win after the event rather than before the event.
The third rule is to get out when you have nothing. If there is nothing in your hand that is capable of winning the hand, do not bother staying in. You are fighting a war not just a battle. You want to be there at the end so it's best to withdraw and be ready for the next one. This is another of those rules that keeps working in your favor, particularly when your opponents ignore the rule. Treat any money that you may have contributed to the pot as 'gone money', ie unrecoverable. Once it was in the center, it was no longer yours. So do not try to recover it through foolish actions. Let your opponents lose their shirts by playing foolishly.
The fourth rule is to get out when you have a beaten hand. If you can recognize that your opponent has a better hand and that is is highly unlikely for you to better him, best to forget that hand. Just because your money is in the ring, there is no reason to throw good money after bad. Live to fight another day. Why give him more than you need to?
The fifth rule is to recognize when you have the best hand and then make your opponent pay. There are no friendships in the game. You will be given no leeway nor should your opponents expect any either. There are a number of different betting strategies that can be used in this scenario, but whatever you do, make sure that you make your opponents pay.
So that's it. Sticking to these five rules already puts you one up on the normal poker player.