This is advice I've been giving myself and living before I attempt to jump in:
1. Get really good at your craft, in this case, programming. You don't want to spend time learning how you need to configure your server when you'd rather prepare for your meeting with that client.And importantly, you have something to fall back on if it doesn't work out.
2. Get enough people to take you seriously. I mean really, work on open source, maintain a blog, attend hackathons etc. Build a decent enough profile that another developer would recommend to someone.
3. If possible, get paid while you pick up these and many other vital skills. You'll learn a lot on the job and clear your bills. Of course, make sure you're sincere enough to focus on 1 and 2.
Young and relatively inexperienced programmer here. Been working for someone else since about a year now (soon after graduating) and plan to continue to do so for at least another year. I've been living this advice for a while now and I feel I'm coming along ok. Would love to hear thoughts from much more experienced programmers/entrepreneurs.