There's plenty of people I've met which haven't directly contributed to my bottom line, but to try to look at everyone as a potential $ is a wrong approach. I enjoy trying to find referrals for other people I meet, and I think that's come back to me a few times (unexpectedly, but not that surprising, perhaps).
Couple other random thoughts:
"Selling the Invisible" (beckwith?) - useful to read. Not specifically tech-oriented, but will get you in the right frame of mind.
"Million Dollar Consulting" (weiss?) - may give you a different perspective on freelance consulting.
Contact local design shops to see if they need an extra pair of hands on call.
Put up a portfolio website with a phone number. Then answer the phone if someone calls.
gentle yet shameless plug: http://indieconf.com is being held again this year to cover precisely these sorts of topics - how to get clients, how to not get ripped off, etc - we'll have 18-21 sessions total - I'm confirming them with speakers this week, so the site doesn't yet reflect the full schedule.