If you are playing in a poker tournament, your strategy will differ dramatically from how you would play in a normal ring game. This is because the essential goal of the tournament is different than that of a ring game. In the ring game, you want to play as mathematically correct as possible in order to convert a long term playing career into as high of a win percentage as possible. There will always be times when you deviate from the most correct play when you suspect bluffing on behalf of your opponents or you yourself is bluffing. This does not change the fact that a ring game is about a long term profit.
A PartyPoker.net tournament is different because you are looking at survival of the fittest over the course of just a few hours. The biggest difference here is that if you lose all your chips, you are out. You can’t simply buy back in like you would in a ring game, you need to make decisions that will allow you to stay in the game as long as possible. This could very well mean straying from basic strategy if you believe it will pay off in the short run. Most of all, you want to conserve your chips for the end of the game. Having one chip left and being at the final table is much different than having a ton of chips only to lose them all over the course of a few hands when the tournament is just starting. The longer you survive in a tournament, the more likely you are to finish in the money.