when you are chip leader by a wide margin you want to win by aggression. not by having the best hand. If you happen to have the best hand, that is a bonus.
so what does it mean to win by aggression? it basically means betting in position. you have room to take a stab, be wrong and fold. THEY DON'T. that is your power. You will win many pots you don't deserve with this approach.
don't try to call all-ins as that requires having the best hand to win.
DO try to flat call bets in position and steal the pots later when the opponent gives up.
Select your hands so that your post flop decisions are very easy. for example it is much easier to play 67s post flop for a raise than it is to play A6o. although technically A6o is the stronger hand your decisions with 67s will be quite simple. You'll usually know fairly easily if you are value betting, bluffing or semi-bluffing. I don't recommend many naked bluffs even as a big stack unless you have position or a read or ideally both.
contrary to popular belief, do NOT pick on short stacks. let the other players assume that risk. short stacks have nothing to lose...variance is high with them. attack weakness or perceived weakness in medium stacks, and it will pay dividends. Try to look for "no contest" pots where there is very little interest or resistance in that particular hand and ATTACK those pots with your big stack.