We seniors tell a joke among ourselves: You know you are getting old when “getting lucky” means you could find your car in a crowded mall parking lot. But you can improve the odds and practice parking lot safety by making your vehicle stand out among the sea of parked cars.
Savvy airline travelers tie distinctive colored ribbons on their suitcases so they can quickly spot them in the parade on the moving baggage carousel. I mark my 2003 Ford Focus by tying a ribbon of red fluorescent surveyor’s tape to tip of its radio antenna. Most new cars have internal antennas, but you can attach a temporary antenna to serve as a slender mast festooned by ribbons.
Go to the toy store and pick up a child’s bow and arrow kit. The arrows are tipped with suction cups. These are long enough for your purpose, and by moistening the cup and pressing it down on the roof, you'll have a stable but temporary vertical appendage where you can attach the colored flag car marker while the car is in the parking lot.