If a trusted friend or family member has a vehicle that's the same make as the one you want, ask who sold it to him or her. A car salesman located by word of mouth is more likely to have been with the dealership for a while, which is a good sign in the high-turnover auto sales field.
"If they've been there awhile, they've probably had repeat customers," says Allen Banez, founder of LetterChamp LLC, a consumer-advocacy service in Tracy, Calif. "That way, you know they're honest."