A sound general tournament strategy is to play tight/aggressive, meaning play very tight and play the hands that you do play very aggressively. So many players will be staying away from hands they can't make good money on, unless they are short-stacked and desperate (read: loose), or big-stacked and trying to bully players around.
The smartest play is picking on the middle-stacked players. You should be able to figure out a player's style fairly early on, so chances are those who were going out guns a blazin' have either been knocked out or are dominating the table/tournament. Those who are more conservative will be counting their chips more (especially players new to tournament play, who will be used to their home games and be playing extra tight with their entry fee.)
Put these players on the line and bet according to the size of their stack to put them on a decision for their money. They are neither behind nor ahead. Even when they are not pot-committed, they can fold for a pot that is still a good pick-up. And they won't have enough of a bankroll to be able to bully you around if you ever try to make a move. When someone has more money, it's easier for them to call a raise knowing that, worst case scenario, they'd be short-stacked but still in the game. But when someone is middle-stacked and calling would mean putting their tournament life on the line when they are still in a decent position, would sooner fold and keep playing rather than gamble and play impatiently. So, when you can, pick on the middle stacks and get paid off..