this day and age start recording video as soon as you walk out of the car to record the damage, record the guy who hit you while you hold up your phone so he knows he's being recorded. also record his plate info, insurance info.
if he doesnt want to talk while being recorded just shut it off noting that he doesnt want to talk over the video.
if he's at fault he will admit hitting your car just from being in shock. unless someone was hurt or a pretty major accident i dont call the police and just report to my insurance guy to take care of the rest. been bumped so many times off and on in my dd it's like a frikken routine.
another reason why i have a beater in the first place.