As mentioned, networking is a critical. I coach a lot of consultants starting you – although I haven't been here in awhile - and advocate a direct, walk in the door and introduce yourself, approach. It is so unscientific it is absurd but is dramatically effective and fast.
Simple – one page resume/profile of sorts. Don't try to be what you are NOT – ie: if you were a big company, then hire a sales rep, otherwise it is you and your wild talent.
"Hi.. I'm Fred. I do part-time projects and overflow computer technology work. Everything from PC setup and training and virus protection to supporting your network. This is a professional summary – a resume of sorts. May I leave it with you and find out who I could follow up with about this?"
Or something.. something that is easy to say, short, and simple for them to get their head around.
Then, get a card, make a note of when you visited, and any other pertinent information. Follow up in 2-3 days.
Numbers are your greatest asset. Once you have the client, don't lose them, and ask for referrals.
Hope this help.
The IT Career Builder's Toolkit
The Matt Moran Band