While I do not get paid to write, or solely to do that, anyways, I do get paid to use my writing skills, which means, of course, that I have to keep them at a high level. It is worth the effort, though, just to be able to earn a living related to something I deeply enjoy.
I am currently making a living both as a writing teacher and a marketing generalist, but I am also, when I can be, working towards becoming a professional writer. Instead of getting another degree (I mean, Jesus, I already have an M.A. in Literature), I have chosen the trial by fire method: self-publishing.
When it comes down to it, I have a hard time letting go of control, and while I don't mind working for others--in fact, sometimes it can be downright enjoyable when you find the right job--I am adamant about pursuing a writing career over the long-term. Any time I am performing the task, thinking about the act or teaching it, I am working towards figuring out how to get paid for it. When I am successful in my marketing and copywriting career, I will have learned the required skills that I need to eventually become a successful writer, if I am willing to continue working towards it. Persistence, I believe, is the key: always figuring out how I can become better at the task, and always working towards the goal.
In order to be successful as a writer, you need to make it about your skill, and you need to understand that it's not just about what you produce with it, it's also how you make an effort to best reach those who you intend to reach, with whatever means necessary, and that means figuring out the most effective means of doing so. I believe it also helps if you enjoy the process, and are willing to accept the highs and lows and chalk it all up to experience.
It's all about, in the words of Will Ferrell as George W. Bush, "Strategery," and maintaining the necessary toughness that it takes to make it through the early stages. It also, I think, becomes about maintaining a connection with yourself: who you are and where you came from, because the thing that scares people the most is dishonesty, even though it seems like we are all dishonest with each other and ourselves all of the time.
That means that you just have to keeping loving writing, no matter what, because, when it comes down to it, it's all about the writing anyways. Does that mean that you shouldn't try to make a living doing it? No, but you do have to have an eye for long-term success and not expect it to happen overnight, and not wait around for it to happen, either. If you want things to happen, you have to make them happen if they are going to happen at all.