I teach Vy to 1000 AGl on takeoff and then climb at the high end of the POH recommended normal climb. If this speed gives you a climb of more then 500 feet/min then increase climb speed until you stabilize at 500 feet/min, assuming terrain/direction of flight/hazards etc are not a factor
For the C 172 P that means Vy 76 kts to 1000 feet then a minimum of 85 kts or higher as necessary to maintain 500 feet min. If 85 won't give you 500 feet min take what you can get. Prolonged climbs at speeds below 85 are to be avoided to ensure good engine cooling