If you have always wanted a calm horse that you could ride anywhere at anytime and nothing would spook him. I think that most riders would, that kind of horse would excel at any kind of work. The best thing you can do to create a calmer horse is to scare him. That's right do as many things possible that would cause your horse to spook. Within reason that is, I'm not saying that you should saddle up and ride in the middle of the city. Just do small things around the barn like make alot of noise when you're doing barn chores.

The more your horse sees and hears the calmer he will be. If loud banging is normal around your barn the less likely he will be spooked when it happens at a show or trail ride.

All too often people will stop an action that scares their horse, like if you where waving your arm to swat a fly and your horse jumps what you usually do is stop the action. "Oh poor boy did I scare you". When you stop moving your arm that teaches the horse that when something scares him and he spooks it goes away. That is the complete opposite of what we want.

If your horse spooks when you wave your arm keep waving it until he seems less worried. Do that with many objects and noises, the more the better. Just remember when he seems worried keep the motion or noise going until he relaxes by lowering his head, blinking his eyes, licking his lips, or just standing still for ten seconds. The more things you expose your horse to the calmer he will be.