Having trouble renting, suggestions?

[James Erickson]

I primarily manage duplexes, triplexes and single family homes. The units are in great condition and the interiors are very nice though the buildings were built many years ago. The units are all located in the now older, poorer part of town. I am having trouble renting the units as some have been vacant since April. I post a sign in the window with my number and I advertise on craigslist and Zillow which posts to other sites. The qualifications are pretty standard like 3 times the rent in income, good rental history but no credit check. If I checked credit I would probably have to disqualify nearly everyone who applies. For instance, I have a 2BR/1BA apartment renting for $550 a month water paid with a $200 deposit and I just can't seem to move it. Trust me when I say the units are very well maintained, the owners pour a lot of money into their properties and I always get comments on how nice the places look compared to others prospective tenants have looked at. Any advice on what I can do to rent these places quicker?