Analyse the situation
First you need to analyse the entire situation. You need to check how strong your opponent is, how many people are involved, what is your weight against your rival’s weight etc. You need to know your limits and if you know you stand no chance against your opponent, run away.
Fight or fly
You need to decide whether you want to fight or fly. In case your rival is an ultimate 420 pounds body builder and you weigh only 120 pounds then you stand no chance against him.
Try not to be violent
In the start, you need to act that you are not going to fight and endure few punches. Act it doesn’t hurt and by this it is possible that the attacker may back out.
You need to assume that your opponent is a trained fighter and thus you should never underestimate him. It is possible that the attacker will mock you, make fun of you and laugh at your non-violent attitude. You need to be ready to feel the pain.
Tire your opponent
Take punches and feel like a brick i.e. you do not feel pain. Do not attack first and jump around in order to confuse your opponent. You can duck, dodge or circle them.
Watch for lack of speed
When you see your opponent is hesitating or slowing, punch him in the jaw and use your shoulder for power. Later you need to knee them anywhere preferable in stomach.
After hitting your opponent and when they feel much pain to continue, you need to flee from that area. Capitalise on his situation and go away from the area. Remember not to run but it should be fast enough so your opponent won’t stand again and fight.