For most mid sized cars the recommended tire pressure is 32 to 35 psi. The recommended tire pressure should also be documented on the information plate on the outside edge of the front drivers side door and on the tire itself where the tire meets the wheel.
Check the tire placard in the driver door frame, in the glove box, in the trunk, or in the gas door. Otherwise use 32 psi for small cars 35 for large cars.