Realistically? The headlock followed with some type of hip-drag to the floor, where you hit them with effective ground and pound. All of those drastically reduce the chances of you getting hit and they're relatively easy to do and gives you complete control of the situation.
Otherwise, I like the "cheap shot" tactic. It's not hard to judge a scenario and foresee yourself getting hit. Some people like to fight for the social side of it, and don't care about reason. Quite a few times I have been in a scenario where some chav (or wannabe gangster to Americans) has wanted to fight me for the sake of it. In this instance, as soon as I think they're going to attack me, I punch them directly in the nose. It baffles them and ruins their vision, where I then use my headlock tactic or I continue punching them directly in the face. Yes it's a pussy move, but I go home fine and they tend to have a broken nose or something that makes them think twice going after you again.
As always though, defuse the situation with words before any violence is necessary.
Edit: Makes me seem like some sort of wannabe badass. Trust me, I have come off worse quite a few times, but they seriously do not come after you again if you show that you can pack a punch.