They put a FOR RENT sign on the lawn and depend upon word-of-mouth.
I would recommend driving around in the neighborhoods you are interested in, and looking for the signs.
Granted, gas isn't cheap, but neither is TIME.
I'm currently carrying a couple of rental properties myself. One is a 3BR, 2.5BA house in the Mt. Carmel section of Hamden and the other is a 2BR, 2BA townhouse-style condo in the Westville section of New Haven. If you'd like more info, please email me at EmbarkWithMARK@GMail.com.