One thing I do is have lots of obstacles (ground poles, barrels, cones, etc) set up throughout the arena. My horses NEVER know what we are going to do! I may be trotting around the ring, and turn in and decide to run the barrels, or maybe turn two barrels and then go over the ground poles, or maybe turn all 3 barrels and then trot the ground poles instead of “running for home,” we may be cantering around and turn across a jump in the middle, or go around a cone. You get the idea – mix it up, keeps them interested and listening. Mine never try to “second-guess” an announcer at a show, because they KNOW I am weird! LOL!!