Cognitive shuffling is a mental exercise to help you fall asleep that involves focusing your mind on strings of unrelated words. Take a second or so to visualize each word. You start by taking a random word — “Pluto,” for example. Then think of as other words that begin with the same first letter, like so: “Plane, poodle, play, peaches.” When you run out of “P” words, you move to  “L,” words, etc. It tricks your mind to abandon the replays of past and future thoughts.