I like to say when I start writing something new that it is always hard and it always feels like I'm doing it for the first time. I always wonder if I can do it again. I always wonder how I ever did it before. BUT it is also like going out on mat and doing martial arts--sparring with someone. If I know the moves, I can't think about them in order to do them while I'm doing them. I just have to do them. In writing once I get into a story, get into the moment, the moves come back even if I don't/can't consciously think of them. Years and years of constant hard work and conscious effort on aspects of craft and practice and struggle come back so that I make the right choices.
You can't think your way into a manuscript while you're writing it. Later, in revision, there will be plenty of time and need for analytical thinking. But when you're writing it's best to pay attention to something Annie Dillard once wrote. "You’ve got to jump off cliffs and build your wings on the way down.” You have to write from that place deep within you and beneath your conscious mind which is all too interfering in the intuitive connections stories require—then you will be jumping off some cliffs and building your wings on the way down.
Wear a helmet and kneepads.