I'm now self employed for 4 years and I earn 6x as much as I earned in my last job. (though I believe I was underpaid in my last job)
He said it, contacts and social skills.
One other way is referrals but you generally need to have a few clients before that starts happening.
I'm curious too, because that's what everyone says, but they stop there. It's always:
1. Have contacts and social skills 2. ??? 3. Make 6X as a freelancer!
Let's say I'm starting with contacts and social skills. And a mortgage and a full-time job that lets me pay it. Any good books or blog posts that describe what's in step 2?
Step 2 - make sure you have enough money put away to last for at least six months with no work.
Step 2.5 - put some stuff on github, publish your cv, prepare to talk to and turn down an absolute ton of agents who will try to talk you into totally inappropriate work.
Step 2.75 - find a decent project to join, work your ass off getting up to speed and contributing fast. Build a reputation.
Step 3.1 - goto 1
The agent thing is a constant in contracting. They'll tell you "you're dreaming, you'll never find the money you're asking". They'll tell you "you need to be able to move around the country for work". They'll tell you "there's nothig contract based around anywhere right now, you need to look at my permanent roles". Some will even tell you you're awesome amd perfect, and then you'll never hear from them again.
But then a good one eventually comes along.... and gets you a well paying contract in a broken team doing something pointless. But hey, the money's good and you're only there for a few months so what does it matter?
Edit: My point is that freelance work income may not compare, but the income may not be the reason for moving to freelance. The op did not explain why he moved to freelance, but I can think of some great reasons to do so.
If I didn't have paid vacation days, I doubt that I'd ever take one. They'd simply be way too expensive. It's one thing to use paid vacation days, another thing entirely to give up over a week's worth of income. I don't think I could do it.
Top independent freelance software developers can make $300k if they work hard and have a good network, as can top big corp engineers. Of course, neither is easy to achieve and the metrics are different. (Freelancers are valued on their results, big corps hire on pedigree and games.)
I personally value the autonomy over almost anything else -- I can live in a low cost-of-living city with my wife for half the year, go skiing/mountain biking over lunch, and overall spend more time among the people I care about. But that does come with all the stress of building a client base, chasing down payment, explaining to non-technical people why their ideas aren't feasible and I can't build Siri in 3 weeks, etc.
There are two essential skills required to manage your own freelancing or consulting practice. The first is the core competency for which you bill (software development, sales conversions, security auditing, etc.). The second is the ability to inspire confidence in your clients that you are capable of using that competency to solve a business problem. Perception matters a great deal in business relationships and framing yourself as an equal who will leverage a unique mix of skills to contribute value is very important.
'patio11 has spoken about this a lot, and his writings helped me get to ~$300k per year as a consultant.