Know their rules and be nice. I've had surprisingly good experiences with a company with bad rep.
Once i rented a car for 3 weeks for 0.73cents a day in low season. A fiat panda in south west europe. Im local there so it helped.
Always make a chitchat with the person in the counter, get their name and ask them how i can avoid any issues. They are surprisingly nice and i can always name drop their name to the final inspector so they think i know them. ... Or just buy their insurance.
Havent rented since covid thought.