As we say in the Boy Scouts,"Be Prepared".Some of the courses I have taken emphasized that the mind is the real weapon, everything else is a tool. I draw on my military experience and my graduating from TOW school and teaching anti-tank tactics. You can destroy a tank by blowing it up, but you can also defeat it through a firepower or mobility hit. Go for the eyes, the nose, the throat, remember that many ordinary items can be used in self defense. A key ring makes a good improvised brass knuckles, a pen or pencil a good stabber.
And having read-and re-read-Charlie Askins' works, I recall clearly his description of the "belly gun"-"You put it against your enemy's belly and pull the trigger!" I think we tend to overlook that a firearm is just as effective at point blank range as it is farther away.