Plantser

Some people, like me, call themselves “plantsers,” which means they’re do a little of both. In reality, most people are plantsers, but some tend to lean heavily to one side or the other.
A plantser could be someone who—before writing—writes a synopsis and comes up with important details that drive their story ideas. Or they could be the kind of writer that enjoys planning out their subplots and character sketches and character arcs, but during the writing of the novel, goes rogue for some chunks of the story. They like a taste of writing life on the seat of their pants—but not all of it.
Personally, I think a great plantsing strategy is to look at story arc and outline the big moments in a book. In other words, the elements of plot for the major parts of a book: the beginning, the middle (which has two parts separated by the midpoint), and the end.