Apple Creek Whitetails Photo
Bucks like the advantage of being on the uphill side of a sparring match. Giving the buck a path to respond to rattling which allows him to come in from an uphill location will greatly increase your chances of calling. Be sure to avoid any obstructions the buck won’t want to go around. Ledges, large blow downs and the like often discourage a buck from coming in.
More on rattling deer here