Take a magnet and check around the top of the windshield, quater pannels ect for previous body filler. ( if the magnet has a strong bond then theres metal ) :D

Drive the car! go threw all the gears and make sure everything is working properly. Turn off the radio when your driving and listen very carefully for any noises. Check the brakes, oil, and fluids. Also the condition of the interior normally shows how well the car was taken care of :D