The first thing you have to bear in mind is that online poker is rigged. The online casino makes it's money by raking or taking part of the pot. So the casino rigs games in a several different ways to increase their rake.
Here are some simple rules for playing online poker. If you obey them you’ll immediately win!
1) Always play any hand and at least take a look at the flop especially if you are UTG.
2) If you receive big hole cards (AA, KK, QQ, AKs, etc) be cautious. If you flop a monster hand check the board and see if anyone else could have the nuts or draw the nuts. If there is a chance of someone getting a better hand it will probably happen.
3) Always chase flushes and straights. you will be suprised how many you will hit on the river.
4) If you flop a straight or a flush, fold immediately. If you flop a straight someone will get a flush and if you flop a flush someone will get a full house.
5) If your stack is getting a little short, just push all in. Chances are you will win regardless of what you have. You do have to keep in mind that someone with a smaller or equal stack may call you though.