This is a technique I have always struggled to incorporate into my writing routine, but I know other writers who have sworn by it: set a timer when you sit down to write. It can be for fifteen, thirty, forty-five minutes—however long you intend to write before you take a break.
When you have a timer going, it really alters your perspective of what you are doing and what you need to focus on, therefore allowing you to quickly get words on the paper and not worry about how they sound just yet. It provides pressure to write without stopping to let yourself overthink or try to edit as you go, and is a great technique for when you are just starting out with a first draft and are still in that “word vomit” stage.