I am mainly focusing on the first law of motion:
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an outside force.
Simple enough, and quite amazing when applying it to writing. If you keep working at it I find that new ideas will pop into your head throughout the day without too much thought. Constantly keeping the cogs turning in your mind allows for new ideas to form even when you aren’t concentration on them. I find that if I’m doing something physically active it allows for my brain to work through kinks in the story that need to be ironed out without me having to be concentrating fully on them.
There is a Big Bang Theory episode where Sheldon does this exact thing. I like to think he’s a bit more eccentric than I am, but who’s to say.
So, stay in motion with your work. Keep on writing, and ideas will come to you without you even realizing they were there. If those creative juices keep flowing it makes the writing process that much smoother because you aren’t sitting down wondering what to write about next. The ideas have already formed (tentatively) in your head, and now all you have to do it put them on paper!