One of the hardest things for me to do is write a process statement, which many shows require. I have, um, several processes and it's rather random which one I use on any given painting. My main process is Whatever the Painting Calls For, which is not a good answer to the question. One of my methods is Painting in Layers, often involving a technique called Back to Front, possibly in combination with Top to Bottom, and sometimes including Underpainting or Color Sketching.
But not always. Sometimes it's Middle Out and others it's Light to Dark. Or Dark to Light. Oh, and Grid & Transfer, not to mention Diving Right In Without Bothering to Sketch.
In any case, one thing that plagues all of my methods, with the possible exception of Section by Section, is Forgetfulness. I really hate this method, but it loves me. I think to myself, Now don't forget to put a treeline in over there. And I do remember... later, after the painting has been photographed, varnished, signed, and is hanging on a wall somewhere. Why not do it in the moment, you might ask. Fair question. Well, possibly, the paint is too thick/wet to take another layer, or I need to paint something else first, or I'm scrambling to wrap up so I can go pick up my kids, or the palette is full of paint so I don't have room to mix it. Whatever. I have simply gone on doing the same thing (talking to myself) and getting the same result (forgetting).
One of my favorite things to do while painting is listen to podcasts. I was listening to my current obsession, Happier, and they were interviewing the host of anther favorite, Note to Self, and I thought, Aha! Voila. I have hacked my studio process(es) and have a new, over-arching method that works: Notes to Self. Yay, me. :)