First, lets look at what most often happens when novice players get a big stack; they either
open the range up far too wide or
tighten up wayyyy too much, right into being the Mayor of Nitville! They also play far too many hands, a no-no they might well be aware of and forget when stacked.
If you have been raising 2x the whole game, now is not the time to go 3, 4, or 5x! Just keep playing a solid game. What is nice about having chips is that yes, you can play more specultive hands, and bad, as that can quickly erode your stack! So
be selective about what you chase and ask the all important "if I make my hand, will I get paid off?"
Sometimes you can chase a really good draw, yet it's obvious you might not get much when you do hit your hand - so why bother? If the other guy wants to get to a cheap showdown, he won't pay you off often enough to make it worth the risk. You see this alot with flush draws - the guy bets the flop with two to a three flush on it, then shuts down when the 3rd flush card hits. If he is worried about the flush and short, he isn't going to ram and jam, paying you off. I'm not saying don't play it, just keep in mind you want to hit your draw AND get paid! Not easy. And if the guy is willing to give you horrible
odds to call, why risk it? Sure, maybe 5-12BB's are nothing to you. Add all of them up and you can see yourself quickly losing your big stack. I myself refuse to chase a mere gut shot (4 outs) for 8-15 BB's I might not even get if I do hit!
Chasing draws are still the number two killer of MTT players (playing too many hands no. 1). This does not go away just becasue you have a big stack. Again, play your solid game, but if you should flop a four-flush with an open end straight and think you can get paid for it....
that is the risk you should be taking (lots of outs and a large reward if you hit). Not constantly trying to get Johnny's last 6BB's with your measly middle pair keeps you in the big stack.
I would also set, in my mind, what cards you are willing to call a late postition short stack shove with. If it folds around to the button and he shoves 11BB's, I look down at A-10/99 or better, I'm insta calling (unless I'm sure he has a monster). 66-88 is probably a call, although I'm not very happy. 22-55, and only the blinds and antes with his shove...I'll probably pass. I'm sure I'll hear about that last one, as I see many big stacks call all ins with ANY small pair, even up to 30% of the stack they have! I also see these big stacks get reduced really quick refusing to fold semi-decent hands and losing a few coin flips that really would not increase their stack much had they won. And I also would not be crazy about coin flips with only two overcards. AK can get you shorted really fast against 22 and a desperate short stack or loon with a middle stack who only wants to shove preflop. This is one time I might actually fold AK preflop if it looks like I could be up against one short stack and one middle stack - that's the guy I worry about, the bigger stack. If my AK fails to stop him, I could lose a big chunk on a coin flip, so no thanks.