Go to Bitcoin gatherings and be social.
In other words, in person advertising lol
You'll go to where your potential clients are. Just tell them what you're working on, the Bitcoin community is still tiny and enthusiastic. Reputation matters and if you're good, word will spread. I've met some great people at conferences and MeetUps. We bounce ideas off each other, trade skills, and make introductions to other guys with similar interests.
People are the greatest resource.