While action on the flop, turn and river are crucial parts of the game, decision made pre-flop should be the basis of your poker online game. Any success post-flop needs to be set up well before the cards hit the felt. There are three main things to take into account pre-flop.
Your hole cards will dictate most of your play. An understanding of basic hand values will make life pretty simple for most hands. The lowest tier hands, including low unsuited unconnected hands like 7-2 off-suit or 10-3 off suit should be mucked almost 100% of the time. For more advanced players there are times to play these hands and even raise with them but as a general rule it is the safest bet to just fold these hands. Likewise, premium hands that include pockets pairs above 10s or suited face cards should be raised with most of the time. Hands that fall in between these two extremes need to be played on a hand to hand basis, but the general rule that weaker hands should be mucked will save a lot of problems post-flop.
The second key factor is position. The earlier your position on every hand, the stronger your hole cards need to be to carry on to the flop. A middle hand like 10-9 suited can be played fairly easily when you are on the button, but if you are first to act, a hand like that should probably be mucked. The closer you are to the button, the weaker your hand can be to still see the flop. Position is more important than people think, and it can radically change the range of playable hands you have.
The third key factor is the action that has taken place before it gets to you pre-flop. A hand that has been raised and then re-raised would make pocket 7s or 8s and easy fold, but if there has been no raise before it gets to you, pocket 7s or 8s will seem like a very strong hand.
So the three things to take into account before you worry about the flop are hand value of your hole cards, your position in the hand, and the betting action that has taken place before it gets to you. More advanced strategy will affect all of those things, but making sure you stick to those fundamentals will make post-flop action a little easier.
