The guy who said something about short stories is right.
We're all aiming for the stars but we have to start somewhere. As a writer, you need to understand that you shouldn't have to ask these kinds of questions. Writing isn't complicated: you just sit down and pour your heart out. You decide how to begin, how you'll go about it, and all these kinds of questions. From what I've read, you sound like you're capable of doing that. So no more "how to write a book" questions, kay bud?
And in my experience, 1/4 of the writing process is writing the book itself, while 3/4 of the process is to edit, edit, edit, edit, edit. It's alright, by then you'll love your series and will be willing to sacrifice hours on your book. In fact, you've already said that, haven't you? Good on you.
However, don't overestimate yourself. I started writing in year three, and I'd thought I'd mastered it at fourteen. Don't get cocky like I did, because there's a lot to learn, and you can always improve. But I guess that just gives more incentive to write write write.
Also, use your own personal experiences as fuel for your ideas. Like, when I found myself a really nice boyfriend, I wrote out all my feelings and fitted it into my story. When the bast*rd cheated on me with my best friend, I wrote out all my anger and hurt and fitted that into the story, too.
Ew, I used myself as an example twice. Sorry about that.
ANYWAY, I mean that the best writing comes from personal experience. Go out on things like camping, pay attention to your relationships, etc etc etc. You'll find that your writing improves from personal experience.
OH and read a lot. It really helps.
Also, take a notebook everywhere. I mean everywhere. Except maybe to the toilet.
I'll stop rambling now, hope I helped :)