It is hard to analyze what kind of traffic you get, but I like doing little simple (FREE!) things to attract people to my site. Do you guys have business cards? Do you leave them everywhere?
I write my website address in chalk on sidewalks. I write it on slips of paper and 'forget' them in books from the library relating to my subject matter.
Don't be obnoxious with that last one though - and no braking the rules.