Routine! Bwahahaha! Theoretical, or actual? Let’s try the actual.
The night before I review my notes about the scenes I’ll be writing the next day, which can range from a bullet point to several sentences, depending on how detailed it came to me while I was outlining. I might even flesh that out with more ideas that come to me the night before, on my phone, just before I go to bed.
When it’s time to write, I grab a mug of green tea or oolong (in my TARDIS mug at home, or travel mug when I write in the car or somewhere else), sit down at the computer, and fight off all the things my mind tries to get me to do before I actually go into Scrivener and start writing the scene. If I’m smart, I do some focusing meditations. More often I waste time first. When I finally beat myself up enough to get started, I write for approximately 50 minute sprints, then give myself 5-10 minutes off, then go at it again, doing as many as I have time for in the given day.
Throughout the day I’ll get other little ideas and I note them in Google Keep, to transfer into Scrivener next time I’m at the computer. They could be notes for future scenes, or edit points, in which case I put them in my Editing Points file and deal with them only after I’ve completed the first draft. I don’t do any editing, and very little rereading until the first draft is done. If I need to look back to something from a previous chapter I just note is as <check hair color> and fix it during the first editing pass.