1. You've probably heard this before and it is in fact the most obvious part of becoming an author, and that is sitting down on a chair and actually writing. As Nora Roberts eloquently put it when The New Yorker questioned her about one rule of writing, "Ass in the chair." Do that, because even if you feel as though the words you're putting down are awful, they're better than no words at all :)
2. Set word count goals. I have been doing this since the very first book I wrote - the one that will never see the light of day because of how bad it is. Even if getting published might feel like a distant dream, it will remain so unless you finish a manuscript, which you will do if you decide to write a certain amount of words per day. In the beginning, I wrote about 1000 per day. I now get 3-4K down depending on what other things are happening in my life. We all have family, friends, obligations and possibly a day job or school, but unless you take your writing seriously and give it the time it deserves, no one else will and, more importantly, you probably won't get published.
3. Be determined. Decide that this is what you want to do and do it. Sounds simple, right? It actually is. Even if you don't land a contract with a big publisher, there are so many other options today. Just look at how many authors are self-publishing with great success. And remember, the more you write and the more you publish, the greater your chances of one day grabbing the attention of a big deal editor, if that is what you dream of doing.
4. Get used to criticism. I have never been criticized as much by people I don't even know as I have been over the last five years since I published my first book. The moment you put your thoughts out into the world, even if they are in the form of fiction, they will be judged. The important thing, is to avoid getting hurt or offended, but to use this feedback in a positive way. Because maybe there is some truth to what some disappointed reader out there had to say. Maybe your book was filled with anachronisms or other inaccuracies, or maybe the characters lacked depth or your plot was boring. Whatever the case, being made aware of your shortcomings as a writer (even if you choose to disagree) will help improve your future books and ensure that the next reviews you get are better. So don't sweat it and don't worry. Every author I know has received negative reviews. Because guess what? You cannot please everyone. It's literally impossible.
5. Read. Read as much as you can and then read some more. Pay attention to what makes a book memorable. Why are the characters so interesting? Why is it impossible for you to put down? How does that first paragraph grab you and draw you into the story? There's a lot of extra reading on this out there in the cyber universe, but the best books are usually the ones that elicit an emotional reaction in the reader. They have to relate and they have to care until they've read the last page. It isn't easy, but it can be done. As long as you go back to rule number one of this list and sit down and start writing.