Gearhead,
I do it as a side income that I do not rely on.
(It's just extra cash when work blows my way) I work a full time programming job. Getting PAID is the biggest problem besides finding the work. So I don't look too hard to find the work. It just kinda finds me

Make buisness cards and plaster 'em up everyewhere.
Pass them out to everyone you talk to. The best places are westec eastec IMTS etc....etc..(If they scan your card give them one of yours)
People that go outside thier own company for fixture design, fixture programming and/or part programming are usually in a jam and desperate for one reason or another. Be willing to stay up all night and get the job done quick. They ALLWAYS needed it the day before yesterday

I will not even turn my computer on for less than $30. hr. (and that's if I know you) Base your price on complexity and urgency. It is also comforting for a potential customer to put a celing in your quote. (ie..$70. hr. not to exceed 6 hrs. or $420.) "Trust" is a huge part of this. I had to build the trust of the guys I program for over time, both at my full time job and otherwise.