How to create a direct mail list.

[Dave Klein]

I'm looking to create an direct mail list for owners on the north side of Milwaukee who own buildings of 8-24 units. What's the most efficient way to create a mailing list like this??

So far the best game plan I've come up with is to just manually search a neighborhood on Zillow looking for quality buildings and then search the property the county tax site to find the owner information. Is that really the most efficient way??