The first thing you need to know is that books do not come wholesale from the heavens. No writer I know locks themselves in a room for three days, takes divine notation and comes out with a good book. There are some writers who write fast and can finish a draft in a month or two, but they'll be quick to emphasize the word draft. The words they have are like batter, a delicious mess that still needs to be baked into a cake.
The second thing is that no two processes are alike. Writers, like snowflakes, all have a favorite way of working. Some make meticulous outlines and have the blueprints for their book ready before they ever sit down and write a single sentence. Some, like me, often begin with a handful of characters and a rough idea . They write and see where it leads. Neither way is perfect, each has merits and problems, and whichever works best for you is the way forward. The process can even change book to book—each story presents its own challenges and each time, you have to sit down and figure out how best to meet them.
So, caveats out of the way, here's how I work. I am what in writing circles is called a pantser, that is I tend to write 'by the seat of my pants'. I begin with a vague idea, some form of structure I'd like to use, and a few characters. Then I figure out a 'way in' to the story and I have at it. I write longhand, scene by scene. I write quickly as I can, getting all the thoughts down on paper (regurgitate the thoughts, I was going to say but let's not) I make notes along the side of my notebook, things like "put this first" or "no, no music". I cross out words and sentences. I put things in parenthesis, which is my shorthand for 'think of a better way to describe this' . I put arrows here and there meaning switch this around. I end up with something that looks like a big soupy mess-o-word.
Then I do one of two things. I scrap the scene entirely, because it isn't moving the book forward and taking it a good direction, or I rewrite the scene, pretty much entirely, into my computer. I work more slowly now, stopping to think and breathe. I use the handwritten scene as a template, keeping the parts I really like and getting rid of or changing the rest.
The book begins to come together as I lay out the scenes one by one like ties on a railroad track, but I need to make sure it has life and emotion and that it works. I run through it again, getting rid of stray words and excess wordiness. I unpack some of the emotions—so sentences like "He was depressed." are rewritten to say "Each morning it became harder to find a reason to get out of bed. " Then I hand pieces off to my critique partners to get more eyes on it and take a careful look at their reading and advice.
I rinse, lather, and repeat these steps until I have a story that reads, well, like a story. This is, still, just the beginning. I send it to some beta readers; people who will read the entire book and let me know what they think. I make more changes. Then I still have to interest an editor, who has more ideas on how to make improvements. It's a long process, but when done right, it works. For me, anyway.
If you are a writer, what is your process?