Playing in tournaments and cash games are two completely different types of games. Strategy that you apply to playing a cash game and strategy that you apply to playing in a tournament often do not work in the other type of game. Most players start playing in cash games and then transition to tournament poker and are astonished by how different the style of play is in tournaments as opposed to cash games. Usually, these players spend countless tournaments scrubbing out trying to acclimate themselves to the variations in play. Luckily, there are a number of easy things to remember to make a transition from cash game play to tournament play.
The first difference to understand about tournaments when compared to cash games is the fact that the blinds are constantly increasing. Because the blinds are constantly rising, it is imperative that you participate in pots and grow your stack because, as time goes on, the number of big blinds in your stack will decrease until the point where, what was once a large stack is now an extremely short stack. As a result, when you are playing in a tournament, you should play more aggressively and open yourself up to a wider range of hands than you would consider playing in a standard cash game. You need to win hands in order to make any sort of performance in a tournament and you cannot sit there and fold every hand hoping for the nuts to come your way.
The next thing you need to understand about poker tourneys is that you will have to go all in at some point in a tournament. Because of the constantly increasing blinds, at some point you are going to find yourself short stacked with the need to go all in. As such, you need to make your moves when they arise and go all in and try to double up when it is advantageous to you as opposed to when it is a necessity. Needing to go all-in on a king-ten offsuit as opposed to a pair of pocket queens is a very sad situation indeed.
Another thing that is important to remember is that you are going to move tables constantly in the tournaments so you will not be able to get comfortable and learn what type of opponents you are playing against. As such, you need to focus purely on the cards because you cannot really build a profile and without a profile, it is much harder to make accurate decisions as to what your sort of play style your opponents have or what sort of decisions they may or may not make.
Being able to transition from cash game to tournament poker can be overwhelming and daunting due to the massive differences between the two formats. It is extremely important to remember that the two formats are very different and to play tournament poker much more aggressively because you cannot sit on your laurels and wait for the goods to come to you.