If you have more than one lovable pooch on your hands, you may notice that one is being very vocal. He is barking and growling viciously, and you may think, "Man, this one really wants a piece of me. I'd better focus on him."
Loudmouth over there is the Omega Dog - the sidekick, the toady. His job is to distract you from the Alpha Dog. He's trying to get you to turn your back to The Boss-dog, so that you will be most vulnerable to his attack. This is not to say that the Omega Dog will not go for a bite - he just might. What you need to understand here is that you cannot be distracted to exclusion by the noisier, seemingly more menacing threat.
Try to get your back up against a fence or a wall, so that neither dog can be directly behind you. I know this sounds like painting yourself into a corner, but at least there won't be any sneak attacks while you scan for weapons or a way out.
No Escape, No Weapons, Oh No
There is nothing to play tug with. You haven't managed to transform yourself into an urban gladiator with a garbage can lid and garden rake. And, there's simply nowhere to go. I have bad news and worse news for you: You're going to have to fight the dog, and you're probably going to get bit.
Job One is staying on your feet. The dog will try to knock you down. Once he has you on the ground, he has access to your face and throat, and it will be very difficult, if not impossible, to regain your feet.
As hard as it may be to tear your eyes away from his fangs, try to focus your attention on his front paws. They will be the points of contact. If you can reasonably determine where the dog intends to hit you, you may be able to dodge him, or at least bolster your stance accordingly.
Look around for a rock or some other hard object to throw at the dog. If there aren't any, you may be able to get the dog to back off by simply pantomiming picking something up off the ground. Dogs that run around trying to bite people are likely to have had something thrown at them at some point - usually, an item found on the ground. Dogs remember pain, and things directly preceding pain.
If you have to fight the dog, fight with your feet. Feet are closer and better protected than hands. Kick him where he lives - nose, eyes, throat, genitals. Kick him hard. You are going to have to hurt him badly enough to convince him that attacking you wasn't such a jolly idea after all.
In the most extreme of circumstances, you may have to disable the dog. If he manages to get you down on the ground, super-size your anger and go for the throat. Let loose a stream of white-hot expletives that would curl your mother's hair, and squeeze up and into his windpipe, as hard as you can. Most dogs, even some of the larger breeds, have relatively shallow windpipes, and you should be able to choke him out.