Observe your cat. It is difficult to surprise him. Why? Naturally his superior hearing is part of the answer, but not all of it. He moves well, using his senses fully. He is not preoccupied with irrelevancies. He's not thinking about his job or his image or his income tax. He is putting first things first, principally his physical security. Do likewise.
Jeff Cooper (2006). “Principles of Personal Defense: Revised Edition”, p.14, Paladin Press