Help marketing new bookkeeping service!

Hi,

I am starting my bookkeeping service and am stuck on how to find my first few clients. I know that businesses like mine spread best through word of mouth and I have told everyone I know about my work and that I am looking for clients. Today I plan to put an add in the local paper and I have done some pro bono work for a testimonial for my website. I plan to place an ad on Craigslist, though Craigslist is scary to me, so many scammers and viruses!

Does anyone have any more ideas for me? I would like to start with local service companies, construction, electricians, that sort of thing. I don't have the budget to join the Chamber of Commerce right now, that was suggested to me before. Any suggestions would be greatly appreciated!

Thanks guys!