depends on the situations, when near bubble or when there are large pay jumps late in tourney (let's say 1k man mtt, there are 150 left and only last 50 get decent payout and top 3 get real money
or 9 man sng with 4/5 people left and 3 person itm)
in these situations it's really easy to just min raise any two decent cards if nobody else has raised/limped. It only needs to work about half the time to be profitable and oftentimes if you get reshoved their stack is so insignificant you can make the call - which will again make people even more likely to fold unless they get the true premiums.
If not in those situations just try to protect that stack, don't be aggressive for sake of aggression and remember that people will remember your are doing it and exploit it. Bubble/big pay jumps and be good at calculating pot odds
, if you think you have two live cards and they are short stacked it may actually be mathematically correct to call that AK shove with 27 - but can't stress this enough if you don't know that math then don't make those calls unless it's <5% of your stack of less than 10bb.
Biggest mistake I see big stacks do is over raising, and doing it every time, they are risking far too much for too little and they rarely last long, don't do it every hand - mix it up, try not to do it in position and most importantly, don't do it if someone else in front raised - then you play normal poker not big stack poker. While that guy could likely be trying to steal with 65/QT/AJ type hand he could also be holding the goods and praying you'll do exactly what you're doing. If they raise a lot try a 3bet once or twice just to establish table leadership.
Main thing though is try not to play big pots preflop unless they are <10 bb. Someone with 25bb and AK will be willing to call your QT 4bet shove preflop but reverse situation and he flats your 2.2 bb raise or 3bets to 7bb and flop is J83 it's pretty likely he'll fold and not risk his tourney on A high. Of course there are people that will do that but in general it's easier to push people around post flop and also easier to raise/fold post flop as well. Nobody is going to check/raise or reraise the bully and expect a fold very often.