Most players are aware of the significant advantages that come with having a big stack in a tournament. When a player has chips, he can attack and pick up pots by forcing those around him into a corner where they have to make tough decisions. Those who have short stacks are always vulnerable to attack by those who have managed to accumulate lots of chips.
Why can the big stacks be more aggressive? The answer may surprise you. In tournaments, the more chips you have the less each individual chip is worth, making it easier for the big stacks to throw more into each pot. It's a strange concept, but one you should understand. To illustrate the point, say that you have 100,000 in tournament chips, and you lose 20,000 in a pot. You're not going to be happy about the loss, but that setback is not nearly as devastating as losing 15,000 from a 30,000 stack.
When you have a lot of chips that aren't worth much, you can be a lot freer to use them. You can go after blinds and antes without premium cards, or you can enter into race situations. If some hands don't work out, that's OK, because you weren't risking much to begin with.
The benefits of having deep stacks are significant enough that I'm willing to take some risks early in a tournament that give me the chance to build up my chips. When I'm playing in position, I'm likely to call raises with hands that I wouldn't play in a ring game or late in a tournament - hands like Q-9 suited or K-T suited. In a ring game, with these sorts of hands I'd be worried about being dominated and getting myself in serious trouble if I flop top pair. But early in a tournament, I can call with the hope of hitting the flop pretty hard. I'm looking for two-pair, trips, or some kind of big draw. When I flop a draw, I'll have the opportunity to semi-bluff; if I hit two pair, I might take a lot of chips from an opponent who can't get away from top pair.
Also, keep in mind that there are likely to be a higher proportion of weak players early in a tournament. You want to get as many chips from these players as you can before they bust.
Playing more hands early in a tournament does expose me to greater risks, but I'm fine with that. I'd rather gamble early and bust than cling to a short stack for hours on end. When I'm short-stacked, I know that one bad beat or one lost race will have me on the rail. I'd rather take some chances and try to accumulate a stack that can stand up to a little adversity.
So, in your next tournament, look for situations in early levels that give you a chance to acquire a big stack. You may bust, but if things work out, you'll give yourself a far better shot at surviving deep into the tournament and having a big payday.