I carry my own liability, many companies need you to have a w/c policy. I have a tax ID number and am an LLC. You need to keep your records tighter then when you were an employee.
The self employment tax is an eye opener; you will find that without witholding you owe two to three times what you paid out in the past. When we got married I bumped up a tax bracket and ended up owing 8k the first full year we were together. Forming a C-corp. and paying your self as an employee can help with this.
I would call around to companies that you have a relationship with and ask if they would use you for 2-4 days per month. Quite often it is hard getting a foot in the door, many small companies have never seen a really top end climber, and cannot understand the productivity difference.
Some of my clients are great and cannot do enough for me, they always say the job went faster then bid, so I get a bonus hour or so. Others it is always an argument on pay when the day is done. Some are willing to pay me to help cleanup, to round the day out, others rush to help me pack so they can get me off the clock.
You never get OT and often do not put in full weeks. Jobs can fall through at the last minute leaving you stuck for work. Up untill this spring it has not been a problem for me, but lately I've been having a problem getting three days a week in.
The simple math is at if you bill out at $30/hr, then 3.66 hrs puts you at $200, so 3 days a week with this average gets you 600x50=30,000/yr.
I bill out at an average of $40 and it has been tough making my $600/week goal the past several months. A lot of my once-a-month clients are not calling, pr answering the phone. Work is thin enough that they would rather take a day and a half and keep my part.