The multi table tournaments are very popular and they gain more and more fans because amidst no limit multi table tournaments we can count the WSOP and The World of Poker tour. People try to get into them and they must play multi table tournaments to do this. People avoid no limit because they are scared of what they can lose and you can see rarely no limit games outside a tournament.
At the beginning of a no limit tournament you must keep in mind that you are not playing your average no-limit ring game. Keep the bluffing in modest limits because as you will see, because of so many people, the chips each one is smaller than the pot. And this means you can lose much more bluffing than you can actually win, so bluffing is usually out here. So, when still at the beginning, and when your stack is comparable to the stack others have, you should try and play by the rules, do not push your luck and gamble as little as possible because gambling just does not pay off here .
When coming to the middle of the tournament, if you made it that far, you will need to change the strategy. Here you must focus on stealing the blinds and you will experience the side effects of the gap concept: it will take not so good hands to steal the blinds but you need much larger hands to call that raise or any raise at all. In the middle rounds everyone will just try to survive, so act accordingly. Increase the chips you have one bi tat a time and have patience for them to grow. Without, of course you already have a very big stack in which case you should be in control, raise a lot and attempt to get others out of the game.
As you approach the end of the tournament, the blinds will become very big and the stacks will do that too. So, if your stack is low you can wait in the pre-flop for the opportune moment and go all-in. When having a big stack, be aggressive and, again, try to control the game by any means.
Going all in should aim for the best hand, but for at least a marginal one like a pocket pair or an ace with a good kicker. That should give you a nice slice and should keep you going for a little more.