Accurate Rental Comps for Smaller Properties?

[Korok Chatterjee]

Potential first-time REI in the San Francisco bay area. Rental rates here tend to vary sharply between neighborhoods and change rapidly (especially these days). Sites like Zillow seem to compare properties that aren't all that similar and their rent estimates seem inaccurate.

Does anyone have a solution to this problem? Has anyone had issues with accurately pricing rents? Services like Costar and YieldStar are geared towards much bigger properties than what I'm looking at.