1. Bring a gun. Preferably, bring at least two guns. Bring all of your friends who have guns.
2. Anything worth shooting is worth shooting twice. Ammo is cheap. Life is expensive.
3. Only hits count. The only thing worse than a miss is a slow miss.
4. If your shooting stance is good, you're probably not moving fast enough nor using cover correctly.
5. Move away from your attacker. Distance is your friend. (Lateral and diagonal movement are preferred.)
6. If you can choose what to bring to a gunfight, bring a long gun and a friend with a long gun.
7. In ten years nobody will remember the details of caliber, stance, or tactics. They will only remember who lived.
8. If you are not shooting, you should be communicating, reloading, and running.
9. Accuracy is relative: most combat shooting standards will be more dependent on "pucker factor" than the inherent accuracy of the gun.
10. Use a gun that works EVERY TIME. "All skill is in vain when Murphy (Murphy's Law) pisses in the flintlock of your musket."
11. Someday someone may kill you with your own gun, but they should have to beat you to death with it because it is empty.
12. Always cheat; always win. The only unfair fight is the one you lose.
13. Have a plan.
14. Have a back-up plan, because the first one won't work.
15. Use cover or concealment as much as possible.
16. Flank your adversary when possible. Protect yours.
17. Don't drop your guard.
18. Always tactically load and threat scan 360 degrees.
19. Watch their hands. Hands kill. (In God we trust. Everyone else, keep your hands where I can see them).
20. Decide to be aggressive ENOUGH, quickly ENOUGH.
21. The faster you finish the fight, the less shot you will get.
22. Be polite. Be professional. But, have a plan to kill everyone you meet.
23. Be courteous to everyone, friendly to no one.
24. Your number one Option for Personal Security is a lifelong commitment to avoidance, deterrence, and de-escalation.
25. Do not attend a gunfight with a handgun, the caliber of which does not start with a "4."
If the Marines have to paint buildings, why don't they do it here in the U.S.?
Maybe this falls under the heading of diplomacy. If so, then I suppose it can be justified.