1) Stare down at the dog before he really starts making his move, even if you have to slow down and/or walk backwards.
2) Make an effort to move away from his turf or his owner so that he doesn’t feel as threatened while you are asserting your dominance, which is what you are doing in step number. Move slowly; you want to discourage the dog from chasing you, and not give it a new game.
3) Talk to the dog and try to calm it down. I will usually say, “Good puppy” or something like that in a soothing voice to try to calm the dog down and show that I am not a threat. It probably helps that I have a deep voice.
4) If he makes a break for you, stop and bring your hands, arms and legs in towards your body. If you are a man, put your hands in front of your crotch so that the dog can not bite you there. You want your body to be in a straight line so that there is nothing hanging off of you for the dog to attack and grab hold of. Many dogs are just friendly want to play with you or check you out; I don’t assume that the dog going to bite me until it does, but I also do not want to make it easier for the dog to injure me.
5) If you are bitten by the dog, kick it in the head. If you can, try to kick it below its muzzle on its chin as that will cause the most pain while being the least likely to permanently injure the dog. The goal is to give it one good lick that will teach it not to bite runners in the future and hopefully confusing or hurting it enough to leave you alone in the present. Get away from the dog, and call the game warden or your local sheriff at the first possible convenience.
6) Start moving away or continue your run depending upon whether the dog just wants to sniff you or is being playful or is still threatening to bite. Unless you were bitten, do not move too fast until there is some distance between you and the dog. You can probably outrun a dog over the long haul, but in sprinting you are all too likely to lose.