Many people cut a bridle path at the top of the horse's mane where the crown of the bridle or halter sits. A bridle path makes taking your horse's bridle on and off easier with less tangles. It also helps prevent the bridle slipping off something that can happen with horses or ponies with extremely heavy manes and small ears.
Before you begin check how long you want the bridle path to be. Measure from the base of the ears back towards the withers. Generally, you can use the length of the ear as a guide. Arabians often have very long bridle paths to show off the arch of their necks