I would humbly suggest that if you don't have answers to your questions, it is not yet time to quit your day job. As other folks in this thread have suggested,

I would humbly suggest that if you don't have answers to your questions, it is not yet time to quit your day job. As other folks in this thread have suggested, being a successful freelancer / contractor / small-business owner, etc is all about dolla dolla bills. It all starts and ends with sales. Your brand, the marketing associated to it - everything is about building connections and making the cash register go ding. Yes, ideally you want to also be competent and produce quality work, but a lot of people who are really good at the tech part are not necessarily good at the bringing-in-the-bacon part. Figure out how you are going to create your pipeline and the actual steps of everything you said, IE: the mechanics of what to do, will follow. Get all that going before you jump into freelancing.