I remember early on in my learning about writing stories being taught Freytag’s pyramid: introduction/exposition, rising action, climax, falling action, denouement. At the time, the simple structure made sense and worked just fine with the types of short stories I was writing at the time.
As my instruction went on, as my stories became more complex, I learned about variations of this pyramid – the straight line of the rising action imitating the “spikes and dips” one would find on a titled EKG printout. No (good) story is a beeline to the climax – there are many small climaxes along the way, with resolutions of various sizes. Not to mention – subplots. (The other piece, of course, that complicates that line of rising action is the length of the story. A short story will have fewer spikes and dips than a novel.)
In grad school, I had the opportunity to take a screenwriting class, during which we talked about the three act structure – which for some reason just clicked with me. I liked the rhythm of it.

While I still teach the variations of the Freytag Pyramid when I teach Fiction (we write flash and short stories in the class), I also teach the three act structure for those students who might be interested in novels. I use a breakdown of The Wizard of Oz and reference K. M. Weiland’s Structuring Your Novel.
For myself, after I’ve filled out the questionnaires for each of my main characters and have cast them all, I sit down with this three act breakdown (exposition, inciting incident, plot point one, rising action, midpoint, second plot point pre-climax, climax, denouement) and fill in what I can about what I see for the story. I still find the corresponding Wizard of Oz plot points help to spur my own story forward.
The most important thing, though, is that despite being a planner when it comes to my writing, I don’t hold myself to what I put down in this document. The story may shift as I’m writing it. New characters might emerge. I might better realize the story I want to tell. This initial outline is just for me to get an idea of the arc and begin to thread in the subplots. This can also help with writer’s block – I don’t have to sit and wonder what comes next because I already know the scene I have to write. If become stuck at a particular plot point, I’ll try writing a different part of the story. An outline doesn’t have to be super detailed – I just find that the more detail I can get down initially, the easier the drafting stage is for me.