My biggest advice would be to read as much as you possibly can, write as often as you're able, and be patient. Every year you'll learn more and have a more solid perspective of what your plan is. Just try to DIGEST the information you read and apply the advice you're given (but ALWAYS consider the source of this advice, particularly in this new Information age and the world of writing online.) Don't be surprised if your goals and ideas evolve, it's bound to happen when you get deeper into something.
Along with the other reads, I highly suggest Jenna Glatzer's book "Make a Real Living as a Freelance Writer." She has an amazing amount of information in there that will undoubtedly guide you in whichever direction you set your sights on. I second the vote for Peter Bowerman's "The Well-Fed Writer," and I suggest you try getting the 2010 edition since it will have the most internet-savvy information that the original editions didn't have. There are many other great books on writing, but these two will give you much of the practical information you're craving right now. Glatzer's book is paperback or Kindle edition, and Bowerman's is paperback or e-book through his website.
I also think you would benefit from reading a blog I recently read about the future of freelance writing. It's called "What Freelance Writers Should Really Fear" by Carol Tice. You can Google her and find her blog. I also suggest following it, as she has great advice about this thing we call "freelance writing."
I've only been in the freelance writing world since the end of 2009. It's a big, big place. I've only recently started to take it more seriously, as in applying to solid gigs and making a schedule for myself to write. I am also finishing my English Literature degree and work part time as a Winery Assistant with my husband who's a Winemaker. I have procrastination issues, and I get distracted easily so I have many demons I'm battling. But I can tell you 100% that it's all in my head and I'm my own worst enemy. As I better learn how to control my own laziness and procrastination (a.k.a fear of success) I know I will make a solid living with my writing. Currently I do article-writing and some copywriting work for businesses as I'm able. Nothing really consistent yet, but I've also made a major relocation and had to move 3 times in the last year. That sort of takes its toll. I hope to have steady writing work by the time I finish my degree this fall so that I can start chipping away at those good old Student Loans that are on the horizon. (Ugh)
I just sold my first piece on CC and am absolutely thrilled. In only two articles I've seen more payoff than any of my articles on Revenue sharing sites or other content sites I've dabbled with. Apologies on the crazy-long post. I am a writer, you know.
I wish you the very best of luck.