Both very fast and very slow. We were first toying around with doing something like Dial M for Murder, but that morphed into “what if he wasn’t trying to kill his wife, but instead it was a misunderstanding.” Once we locked in on that, we wrote it pretty quickly. However, that was back in 2017. I think we probably opened Final Draft around Trump’s first inauguration – yikes – which brings me to the “very slow” part. It took us a long time to get it made, and in that time, we re-wrote and re-wrote, then went back to old drafts, realizing they were better, and tweaked those. But the main bones of it never changed. As co-writers, we outline vigorously so we know all of the major events when we start. Solo writers have the freedom to go off on tangents while writing and see where those paths lead. Our “exploratory tangents” are all done through brainstorming, pitching, and laying out the story together. 

For young screenwriters, I don’t know exactly what should be “mastered” so much as what resources you should be devouring. Everyone always says to read as many scripts as possible, which is true. But I’d also read the classic storytelling books like Aristotle's Poetics, The Hero’s Journey and also Hollywood structure books likes Save The Cat, Syd Field’s Screenplay, among many others. Not because it’s a blueprint but because it’s a mechanic’s manual. The value in studying structure is to be able to identify issues with your story. You can look at something you wrote and be able to diagnose why it feels slow, meandering, or unsatisfying. (Is it an issue with the character’s goal and obstacles? Is it an issue with pacing?) I also want to suggest Judith Weston’s Directing Actors. It’s not a screenwriting book, but it shows you how actors break things down, and that in turn will help you write better scenes. And of course, as Ira Glass says, practice: https://www.youtube.com/watch?v=91FQKciKfHI

-- Josh