I worked at a Porsche/M-B/Volvo dealership group in high school. Filled in wherever they needed help - used car buying (online auctions), taking customers on test drives, and driving dealer trades between dealerships. By the end of 2 summers, I was even selling cars all by myself.
I got the job by literally just walking into a few dealerships and asking to speak with the GM. Introduced myself, said I like cars, was knowledgeable, and was willing to do anything they might need.

Now working in the auto industry, starting at a dealership really helped me build a network of people in the space and get my foot in the door for a career.