I didn't come from a 9-5 job, but did want to get into freelancing from being a CS student. The trick for me was to build my portfolio of paid client work by doing significant discounts for HN members (https://news.ycombinator.com/item?id=6382405). I got about 15-20 replies to this, and got to choose the most worthwhile clients. Fast forward and I'm now working for them at a normal rate. The portfolio has also allowed me to gain new contracts pretty easily.

As someone else said in this thread, the trick is to find good clients who know the value of your work. I generally find ODesk, Elance to _not_ be those places. Try to find them through other means, like HN freelancer threads or local businesses.