Writing “by the seat of your pants,” aka “discovery writing” works better for some writers than outlining does. Read about the rationale for pantsing here.
Advice and thoughts on story structure.
Character arc (aka the internal plot) is essential for a satisfying story structure. You might have tension on every page and you might follow what you think is a winning structure, but if you don’t have a character arc, your story will fail to resonate with readers. Learn the key concepts for character arcs here.