Okay, so the title of this blog is kind of a misnomer, because I don't think you can actually find your one, single, absolute, perfect process. I've written a total of nine complete books at this point (not all of them published or publishable, obviously) and I've used almost as many processes.
For my first book, I plotted out a very specific and elaborate outline. For the next three, I knew my characters and their situation and just dove into the mist. Then I got an editor and she kinda wanted to know where things were going, so I started then next book with the end in mind. In the middle here I wrote an unpublished book that required a very specific structure, inherent to the story, and I had to walk a very strange and specific line in plotting.
Then my editor wanted to know even more about where things were going, so I broke out the big guns. For the next two books I used Michael Hauge's six step screenplay structure to plot my books ahead of time.
That worked pretty well... until I got to the latest book, the first in my Medusa series. I cannot count how many hours I spent trying to figure out how to structure this trilogy. I have three girls. I have three books. Each girl has an arc in each book. The girls have an overall arc that spans the trilogy. It's ten books in one. When I tried applying the Hauge structure to this mess my brain nearly imploded. In the end, I had to just start writing a train-of-thought synopsis, starting from the point where the book opened and guiding myself through ten pages of "and then this happens."
If I've learned anything in my several years and several books of writing it's that as soon as you think you have something figured out, it'll change on you. And you have to be open to that. You can't waste time trying to hammer an unruly story into a process that doesn't fit. If the Hauge structure works for this book, great. If it's better with Randy Ingermanson's the snowflake method, then try that. Or Chris Vogler's the hero's journey. Or Aristotle's three act structure. Or the monkey poo method of plot development.
(I don't recommend that last one, but, hey, if it works...)
The point is, each new book is a different world (and, honestly, you're a different writer) so you can't expect it to conform to the process that worked for any previous book. You're best bet is to just chuck everything you knew before and start fresh. Plot this book in the way that suits it best. It'll thank you in the morning. Hopefully with a nice, juicy publishing contract.