The cacophony of people in any writer’s head will, of course, vary from person to person, just as writing styles vary from writer to writer. But I find that my characters grow louder the deeper into the WIP I get. When they stop talking, that’s the time to worry that somewhere along the line, I’ve derailed. I don’t plot, I just write – some would say “organically.” It’s always a surprise to me what each character brings to the story, their reactions and how that affects the plot. I write character-driven stories, rather than plot-driven – it’s just the way it works for me. It’s right for me, and that’s the important thing. However we write, if it works, it’s right.
No matter which way you write – plotter, plot-driven, pantser, character-driven, the goal is to get words on the page and to keep the voices in your head from totally taking over while not shutting up completely!