Hi
All of my first three clients came from letters I sent to local businesses (doctors and lawyers as that was my niche back then). That was 25 years ago so I'm not sure that would still be as effective today.
Today most clients come from social networking I do, press releases and articles, & word of mouth. I also have a Google Adword campaign.
Good luck!
Diana Ennen
Virtual Word Publishing
www.virtualwordpublishing.com