First of all, congrats on making it as far as you have. You've obviously been playing well (and had a few lucky breaks, I'm sure) to be in the position you are in at this stage of the tournament.
When I think of you're situation, I'm reminded of a hockey team that has played well for two periods, and has a 2 or 3 goal lead. What should they do in the 3rd period? A lot of teams go into a "defensive shell" and just try to hold the lead, and many times this backfires, as the other team gets a goal, gains momentum, and ends up coming back to win the game. What the team with the lead should have done is keep playing the way that got them to where they were after 2 periods.
That would be my general advice to you. Don't try to fix what isn't broken. Obviously you want to try and put more pressure on the smaller stacks by using your advantage as table chip leader, but just keep playing the same sound way that got you to where you are now. The only things that can get in your way at this point is variance/bad luck, and there's no strategy against that.
Best of luck on Day 2!