So, first two cards are handed over, and it is necessary to make the first decision. Thus it is necessary to consider following factors:

1. Force of your cards (the more strongly, the better) - usually it is necessary to play no more than 30 % of hands, only the strongest.
2. Your position (the later, the better) - in the end at you already is the information on rates of opponents, you can make more exact decisions and not be afraid raise.
3. Bets before you (the more limpers (limper - the player speaking call on preflop), the better, raise - is worse) - the more than players, the sweat if your card will drop out not there is more, you lose only small bet but if to you will carry on flop, you will win much.
4. Type of game (passive/aggressive, tight/loose) - aggressive players can lift with mediocre cards, loose players will answer yours raise with a bad card.
5. Your image behind a table - if you behave as tighter (tight player) against yours raise maniacs or owners of really good cards will play only.
6. Force of game yours and - the is better you play opponents in comparison with opponents, the it is possible to play hands more, you receive the at the further stages of game.

I recommend to view this pre-flop poker strategy (poker table). Pre-flop poker strategy: