I somebody over here dot’t reat this somewhere yet. 
USMC Rules For Gun Fighting
*Bring a gun. Preferably, bring at least two guns. Bring all of your friends who have guns.
*Anything worth shooting is worth shooting twice. Ammo is cheap. Life is expensive.
*Only hits count. A close miss is still a miss.
*If your shooting stance is good, you’re probably not moving fast enough nor using cover correctly.
*Move away from your attacker. Distance is your friend. (Lateral and diagonal movements are preferred.)
*If you can choose what to bring to a gunfight, bring a long gun and a friend with a long gun.
*In ten years nobody will remember the details of caliber, stance, or tactics.
They will only remember who lived.
*If you are not shooting, you should be communicating, reloading, and running.
*Accuracy is relative: most combat shooting standards will be more dependent on “pucker factor” than the inherent accuracy of the gun.
*Use a gun that works EVERY TIME.
*Someday someone may kill you with your own gun, but they should have to beat you to death with it because it is empty.
*Always cheat = always win. The only unfair fight is the one you lose.
*Have a plan.
*Have a back-up plan, because the first one won’t work.
*Use cover and concealment as much as possible.
*Flank your adversary when possible. Protect yours.
*Don’t drop your guard.
*Always tactically reload and threat scan 360 degrees.
*Watch their hands. Hands kill. (In God we trust. Everyone else, keep your hands where I can see them).
*Decide to be AGGRESSIVE enough, QUICKLY enough.
*The faster you finish the fight, the less shot up you will get.
*Be polite. Be professional. But, have a plan to kill everyone you meet.
Be courteous to everyone, friendly to no one.
*Do not attend a gunfight with a handgun, the caliber of which does not start with a “4”.