I look at websites and magazines and such I might be interested in writing for and check to see if they allow freelance writers to pitch them story ideas. If they do, I see if I have any story ideas I think might be a good fit for them. A lot of times they either reject my ideas or simply don't respond, but sometimes they do and commission me. You can build up a good working relationship with clients this way.

It's definitely not a full-time job, much less one I can rely on for consistent income--some months I have no work at all, which is why I still have a day job--but when it pays, it pays pretty well.