I’ve been reading about writing for years, and am often puzzled by the differences in what different people tell you are essential, approaches to various aspects of writing. I am usually skeptical of “essentiallism” and “only one way” approaches; one of my teachers, Mary Robinette Kowal, once said in one of her Patreon classes that “all writing advice, even mine, is what worked for that writer.” So I focus on what seems useful to me in my current state as an aspiring writer.
At the moment, what I’m working on is character development for my protagonist and secondary characters. I’ve been mostly plot-driven in the past, and my characters have to a large extent been “cardboard” plot tokens. So I’ve been studying sources on creating character arcs; this is a summary of what I’ve learned.