don't give yourself away

Keep a poker face: Don't complain when losing or show elation when winning. Emotional displays prohibit clear thinking and the proper evaluation of your hand. Don't indulge in unnecessary conversation. Keeping a poker face means keeping the same disposition at all times. Such restraints are very difficult to acquire overnight, but they are essential requirements of a good poker player. When you achieve them, not only will you play your best game, but your opponents will not be able to figure your hand so easily.