Being a poor student who scrapes a living through Rentacoder, Its difficult to explain further without getting lost when someone raises an eyebrow at freelance web design.
Personally I prefer to have no more than 3 projects happening at any one time, But its a risky job to have as your primary income, So you take what you get, when you get.
Its definately a great place for making some quick cash on the side. And I've always enjoyed being able to have a bash at new challenges I might not find elsewhere.
Get the word out about yourself among people you know, put up some Google AdWords targeting your area, put some SEO focus on "[city] web design", and have a decent portfolio online. I always tell potential they can find a much cheaper way to get online, but that your work is of much higher quality (more attractive design, WordPress or ExpressionEngine so they can update it themselves, SEO to bring them business, etc.).
I'm an independent technology consultant myself, and constantly struggle to find leads. I've heard mixed results on guru and oDesk ... at the startup where I'm CTO, we've hired people specializing in niche ecomm packages off of elance _dirt_ cheap ... shamefully cheap. Typically from Malaysia.
It's such a mucky business ...