- Sign up to mailing lists (esp. job boards) at your local universities. You will be surprised how many startups post on them looking for short term developers while they are bootstrapping. Obviously choose only the paying ones. Might pay less than market, but good for quick cash.
- Browse Craigslist (under gigs). Don't just focus on local ones. Look at those in cities that don't have a huge tech community.
- Create necessary document templates ahead of time (like NDA, contracts etc..) You will be surprised how many clients (who are hiring a contractor for the first time) don't and they will waste precious time putting these together.
- You said you are unable to show off your work. But how about showing block diagrams, technical summaries etc. (without violating NDA etc.)? Some clients prefer this to looking at code or an application.
- Network with peers including those in associated areas like graphic design, marketing, sales, project management etc.. Established contractors sometimes have extra work that they will be happy to refer to others in their circle. And you should do the same when you are ready.
Hope that helps.