What I do is to spray it on the mane and tail and then comb through it after they are dry after the bath. And then I spray on the neck and legs and haunches (places not near the saddle) and then go over it with a soft bristled brush. Then you can get the face and the ears too. But DO NOT use the brush on the saddle area. It will slip right off. Unless your horse is a halter horse only and you won't be riding them in the next few days. Then feel free to go crazy any where you want.
Then right before the show put some baby oil on the muzzle and above the eyes and make sure the nose is clean and go back over with the same soft brush to release the dust that might have settled.
Hope that helps :)