take self defense lessons.
carry a weapon with you (not necessarily a gun) ,or something innocuos that can be used as a weapon,practice with it as often as possible: try to improve your time of drawing it, precision, drill with it until it becomes second nature to use it when you are attacked.
that big guy would not have acted so tough with a few cuts around the neck, or mace in his eyes, or even a fist with a big ring hitting him square in the temple.