Great question! It didn't take long at all, but I was REALLY proactive. I went to Technorati early on in my blogging and did a bunch of searches for people moving to the Seattle area. When I found a potential relevant blogger, I would write something relevant to that person's home search and then follow up with a blog comment on their post to let them know about the great resource specific to them we had on my blog!
For example, one couple was looking to move to Ballard, so we (my wife and I co-wrote most of our early posts) wrote a post on the history of ballard:
http://www.raincityguide.com/2005/10/10/ballard-history/ - Wed Apr 16 2008, 09:35