Before you start betting like a madman when you get two eights in the pocket, you need to carefully consider all factors involved in solid preflop strategy.
The factors to consider are the number of players, how aggressive/passive the players at the table are, your bankroll, your position, and how much risk you are willing to entail.
Number of players: With 10 people in the game, it`s much more likely that someone else has a strong hand in the pocket than in a short-handed game. Also, you`ll need to be more cautious in larger games, as the chances of someone`s preflop hand fitting the flop will be much better. More competition means stiffer competition.
How aggressive the players are: Assuming you`ve been playing with a few people for several hands, and you noticed some jackass is raising every hand preflop, you`ll want to play tighter. Let the guy win the blinds (big deal) and nail him to the wall when you have a solid hand in the pocket preflop.
Your bankroll: If you have $2 left, you`ll want to play extremely carefully and select one hand to bet on, hoping to get as many players involved as possible for a larger pot. You`ll want to be all-in before the flop is dealt. On the flip-side, if you have $1000 at a $1/$2 table, you can take the high-risk, high-payout bets.
Your position: People in late position have the ability to influence the size of the pot much more than those in early position. This is especially true preflop. (see our page on position for more info)
Your tolerance for risk: Depending on your playing style, you may want to play more or less aggressively preflop. Players who shoot for larger pots, but don`t mind a greater chance for losing a few hands will want to raise preflop, especially if they are in late position. Some players prefer to be as selective as possible preflop, grinding out a winning hand here or there. It really depends on your own style of play, and how you perceive the players around you.
You might also want to consider what cards you have in your hand. Naturally, AA is the best to start with. It helps if your hand is suited or if the cards are sequential in rank like a Seven and an Eight ("connected"). It`s important to understand how your two cards hold up against other combinations of cards though. I good discussion of preflop hands can be found on our preflop hand comparison page. For specific statistics on how your two specific cards interact with the flop, try our preflop calculator.