I used to be a pantser. Meaning I wrote by the seat of my pants. I never bothered with anything resembling an outline, I never even bothered figuring out in advance what the story was really about or how it was going to end. I just sat down and turned my subconscious loose. Some of my favorite authors are reported to have written that way. Rex Stout. Mark Twain. Just to name two.
But as I got older and my stories got more complex, I realized that I had to either impose some kind of order on them or resign myself to writing stories that would ramble on for years. I personally think it's self-evident that Robert Jordan was a pantser. Poor guy. Although considering the cash he no doubt piled up, sympathy may be misplaced. But his story even outlived the author, and somebody else had to finish it. That's kinda sad.
I (briefly) tried the rigid outline approach. Huh-uh. Not for me. What I do now is figure out who the story is about, get a rough idea of the situation they are in and what they are facing, and pin down how things are going to turn out for them. Then, and only then, do I turn my subconscious loose to fill in the details. Sometimes it works.
Other times, like with my current book, it needs tweaking. As I have found while I am in the process of content editing parts one and two. There are too many side trails and fascinating little snippets that distract from the plot. They provide background on the main characters, and they help flesh out the world. But they are irrelevant to the plot of a book that is already longer than I had intended it to be. They are going. I will put them in the next book, instead.
What I am doing to bring myself under control is inserting mini-outline notes as I go along. In each section when a scene, or a group of scenes, will be needed in order to balance out the plot I write a summary and insert the note at the place where the scene will go. Then I make sure that the notes are arranged in correct order and start writing. If it doesn't make the cut for a summary note, it doesn't go in. That still leaves me with the task of chopping out the underbrush that I have already planted, but it should keep more from sprouting.
I got this trick from Holly Lisle's website, where she describes using index cards to do essentially the same thing with hard copy. Anyone who aspires to be a writer would do well to stop in there. She teaches paid courses on how to structure stories. NOT how to create them, but how to make them coherent and internally consistent, and to make them flow well. She also offers a lot of useful free advice.
Meanwhile, I have a battle to finish. Back later.