Just apply your ass to the chair (as someone wise once said, a writer’s only requirement) and for fifteen or twenty minutes, practice getting your attention out of your head, down to some wider expanse in your chest or solar plexus—a place less self-conscious or skittery or scared. The idea is to unclench your mind’s claws. So don’t judge how your thoughts might jet around at first. Eventually you’ll start identifying a little bit with that detached, watcher self and less with your prattling head.