Ask HN: How to learn through freelancing?

I want to become a full-time Ruby on Rails developer. I've read things like this (http://www.quora.com/Ruby-on-Rails/What-are-the-minimum-level-of-skills-for-an-entry-level-RoR-job#) that range from as little as throwing a few sample apps on GitHub to joining a programmer school. However, it may be hard to be motivated to build a few sample apps that have no users, and I don't want to move far away to attend one of these schools. Another option I've thought about is freelancing on sites like oDesk or elance to learn through experience. I'll have real problems to solve, and I can do it from my current location. I could do freelancing for 6-9 months to prepare a portfolio to get the full-time gig. The freelancing only is needed to provide significant experience; I'm not expecting much money out of this. I've got the savings to cover the living expenses. If you've attempted to learn via freelancing, did it work? What were the pitfalls? I can see one issue being that a lot of these online freelancing websites have a lot of people applying for the jobs so it may be hard to get them as a beginner even with some sample apps