Shane Parrish recently did a podcast on this topic with Brian Koppelman. In the podcast, Brian Koppelman talked about how we wrote a single page everyday, however he did would not stop writing once he started. Rather than writing it was a thinking technique using writing as a medium. It was a way to derive thoughts from the subconscious. He also mentions how maintaining momentum is important in accomplishing tasks such as writing.

Also kind of fun to see how scripts are created and how they are revised from rough draft to final draft. https://fs.blog/knowledge-project/brian-koppelman/