Everyone has their own process for writing a book. There isn't a right way or a wrong way to go about it. Some people like to figure out the whole story in advance and outline each chapter. Other people like to just dive in.
The book I'm working on now is my 9th. And I'd like to think that in the process of writing the 8 others, I've learned a few things. Certainly, my process for writing a book has been changing and I think that can only be a good thing.
Essentially I'm a pantser. I've tried the outlining thing and it sucked all the joy out of writing the book. Because I knew what was happening next, I didn't feel any great need to jump in front of the computer and write. The thing I love about writing is how the unexpected often happens, and what you think you're writing about may turn out to be something totally different.
That said, just diving in without any kind of plan leads to a long and painful revision process. So I've compromised. I don't outline, as such, but I do tend to jot notes down on a scrap of paper. Not more than a sentence or two for each chapter, but it's enough. Although I have to say, in my new project, I've already spun wildly away from my notes. I'll have to see if I can spin my way back or I won't hit the ending I have in mind.
The biggest thing I'm doing differently with this project is that I'm letting my CP read my chapters as I go along. I pity her for having to wade through all my clunky first draftiness, but having her feedback on the plot points as I write has been fantastic and has kept me from going off on too many tangents. It's also meant I have to write in sequence. I usually don't. It's something I may do again with future projects - if Laura can bear it!
How has your process refined and changed as you've written more books?