Do not strike the dog or put your hand out. If the dog has been hit by his master or someone else, he will perceive your outstretched hand as a threat. If the dog does attack, feed him clothing'your shirt or jacket. You want the dog to take something in its mouth other than your arm. That will make the dog more aggressive.
Many dogs go for the throat when they attack.
If a dog knocks you to the ground, Kovary advises that you curl up and cover your head and neck. Find the owner of the dog. You'll need to know whether the dog's rabies vaccination is current. Then go to the emergency room. Even if you don't need stitches or any other medical attention, you probably should have a tetanus shot.