Like many answers in poker, it depends. If the table you are at is wild and crazy, you can tighten up, back off and let them all duke it out. Don't sit back too long though or the luckiest of the crazies will soon be the chip leader. If the table is playing tight at this point, steal more blinds than normal. But perhaps one good strategy is, don't get into it with anyone that has more than half of your chip count, unless you're pretty sure you're going to win it.