Well, I was going to reply ... but then you specified that you wanted advice from "successful" MTT players.
Anyway...
Successful, aggressive players (Toto, Ivey, Negreanu, Matusow, etc) try to accumulate large chip stacks heading into the middle of the tournament so that they can exploit their opponents. Having a larger stack allows for an assortment of plays that are not as damaging if you had an average stack. Re-steals, raises for isolation, larger continuation bets, are not possible - and you can make them with confidence.
So how do you play as the large stack?
You bet and raise more. Don't SIT on your large stack because soon enough, the blinds are increasing and you'll find yourself average. Normally, you'd open AQs for 2.5 or 3xBB from MP, but now, you can confidently raise to 5xBB. Not only are you representing a stronger hand, but you force the other players to throw away their mediocre hands. (Hands they would normally call for 2.5xBB!) Your continuation bets become more feared, because you're represented a stronger hand, AND they have to worry about you (possibly) putting them out of the tournament if they mess with you. LOL.
It's a good spot to be in. Increase your aggressiveness and you should see better results.