Start out doing 2 or 3 sites for free - maybe local businesses in your area. Do well and get seo results providing excellent service. Word will start spreading, Link those client sites to your sites. Service will be the biggest draw.
Personally I think captchas suck because half the time you can't read them - many will bail using them. A better choice for anti spam bot blocking is a form that uses a security word or basic math answer.