The key to these small tournaments like you are describing is to vary your play as the tournament dictates. I generally play 6 man SNG's that pay 2 or 3 places. The table usually has a couple loose-aggressive types, a few strong players (in which I include myself), and a couple average players. Early on, the play of the loose players dominates the table. About half the time they get knocked out right away, with the money going to the average players, or they knock out the average players themselves. This leaves the two average, loose players with large stacks and two strong players with shorter stacks.

The good thing about this is they have a hard time holding onto that money. They like to call all-in bets with K-small unsuited if they think they can knock you out. They play to get lucky. The trick is to not get into preflop wars against these types. You want to outplay them, not outdraw them. Be prepaired to drop AQ when they move all-in over the top of your preflop raise, unless you are feeling pressure from the blinds.

My strategy is to play rather tightly until the field is down to about half the players left, then start to make my moves. You have to make your move before it's just two of you left. Try to get them heads up, then get aggressive if you make any sort of hand. Top pair is a monster in this situation. They will call you down with low pairs and draws. Avoid multiway pots unless you have big draws and correct odds. By the time I am heads up (if I make it that far) I am usually playing super aggressively.