1) Read. I don't know a single writer who doesn't also love to read. When you read, you get new plots. Play the "what if" game with someone else's ideas. Also, once you decide you want to write seriously, reading changes too. You can read for style and technical skill. You may be surprised how much you can learn when you begin to pay attention to things other than the actual story. Of course I also recommend reading books on craft. James Scott Bell, Donald Maass, Sol Stein, and Stephen King are pretty much staples for any writer.
2) Edit. A lot of beginning writers (especially talented ones) seem to be under the impression that published authors crap out beautiful, perfect first drafts. That is epic lie numero uno. I'll even admit I really hated editing at first. It's necessary, though. You should be aware that your project will undergo several to many drafts depending on what kind of writer you are. But one or two drafts is not going to cut it. You don't have to edit everything. If you're writing for pleasure and for your own eyes, then feel free to forgo that step. What is not seen by others cannot embarrass you.
3) Backup. I think someone else brought this up to, but that just proves its importance. Probably everyone at some point has felt the agony of losing words due to an electronic glitch. It really sucks. So backup, backup, backup. I use my email and a flash drive. You can never have too many backup copies of something. Maybe you should have a hard copy on hand too. Do not trust Microsoft Word or whatever writing program you use. Writing programs are out to secretly delete your words and cause you pain. Believe it.
4) Going pro. There are a lot of writers who do this majig for a living and love every minute of it. However, don't be locked into the idea that you have to make this your main source of income or you have to get an MFA. You don't. There are plenty of authors who write on the side. I really love history, and I love being able to pursue that and also write. So remember, there are plenty of paths to becoming a writer. If you don't have formal training, don't let that stop you.
5) Write. This sounds like obvious advice, but you must do it to be a writer. Don't get too caught up in the research and the blogging and whatever. If you don't write on a semi-regular basis, you cannot call yourself a writer. There are millions of people out there who say, "I'm going to publish a novel one day." Most of those people will never put a single word on paper toward their novel. Don't be like them! Write. Write. And write some more.
Monday: Sometimes Helpful Nonsense
Tuesday: Flames and Shadows
Wednesday: Girl With A Notebook
Thursday: Somewhere Nowhere In My Kingdom
Monday: Somewhere Nowhere In My Kingdom
Tuesday: Sometimes Helpful Nonsense
Thursday: Girl With A Notebook
Friday: Flames and Shadows