You will be put to the test often in a Multi Table Tournament. Many times, the decisions you will make will involve all of your chips. At such a time, it is nice to have an easy decision. One way to ensure an easy decision is to make a particular choice on a previous street. If you put yourself in a bad spot by committing too many, or too little, of your chips, you are setting yourself up for a hard choice if another player does not react as you desire. The goal is to make a move such that you don't particularly care what your opponent does.
I could go on and on but I think there is a good article out there from someone who actually wins a tournament once in a while. Check out Phil Gordon.