If you asked me how to go about building a novel like a project, I’d begin with a high-level purpose, not necessarily a mission but a general idea of what needs to be done. The goals. Then I would sketch out the resources needed and note what is available. I’d begin to flesh out those elements one by one and then prioritize them in order of importance and dependencies.
With the structure in place, I’d keep putting meat on the bones until I couldn’t stand it anymore and then I’d dive in and start doing. Starting the doing is where I often get in trouble. I begin doing before I’ve built enough around the task. Then, as I’m working through it, I find new elements to explore. I add to the list. Scope creep. Uh oh….
I’m not sure there is a clear way to tell when you have enough structure to begin really writing. I’ve looked over drafts from other writers and I see that some are writing the book in short bursts, doing what I’ve done in the “streaming” mode. I don’t know if they go back then and polish the bits or do it in chapter-sized chunks. My own experience has been to go back and edit the whole from the start, brushing up and brushing up as I press forward into the story. This has not been successful. I can usually manage 40-60 pages in this fashion. However, when I get way out there the beginning gets fuzzy. The part I’m working on is not attached to the whole. In other words, I start writing something new, a new 60 pages that is connected to the first in only the most tenuous fashion. In that new 60 pages, major characters are introduced, plot threads continue to grow. Major characters from the first 60 pages fade. It’s not good.
So, while you can’t plan every detail, I think it is important to do more than I have ever done in the past before trying to set down any real prose… or maybe one never sets down any real prose but just keeps writing and writing, rewriting.