Depends on a variety of factors.
If other player is very passive, and doesn't like to bet; I will play a number of different hands. Limping in whenever I don't have a premium hand to see a flop, and raising preflop with anything strong. If he/she calls the preflop raise, you know they are holding a good hand. Get ready for the flop. No matter what the flop is, bet 1/2 pot. Odds
are, if they didn't get top pair.. they will fold.
An aggressive player, can be a little dangerous. Sit back, play premium hands and look to trap as much as possible. You want to have the mindset of an aggressive player, but you want to show you are passive.