5 tips on how to get it done and keep some sanity https://www.insidehighered.com/advice/2015/11/25/how-survive-and-thrive-during-dissertation-process-essay
6. Write only about what you are writing about. In other words, stay focused; don't try to boil the ocean. No one wants to read how your discipline's roots are from an argument between Plato and Aristotle.