I realised not that long ago that one of my hobbies these days is collecting ‘Rules for writing’ from various authors. One of the first I tried was Stephen King’s On Writing, summarised in the link there, and the core point of that entire book is this:
Writing is a job, so have a schedule and put the hours in.
This is what they all, in the end, boil down to. There might be some fluff about craft and technique, or even about not doing scary things out the window, but a vast number of authors have spent a huge amount of words trying to communicate… that writing is a job.