Things that ZS has taught me
First of all, and most importantly, KNOW YOUR EXITS. If your back is to a wall and you don't know how to escape without taking your eyes off of the attacker(s) then you will get stuck and killed.
Second, KNOW YOUR AMMO COUNT. The last bullet is the most important, because you have to know that as you squeeze the last round you must take flight, rely on a backup, or get ready to reload. Reacting as you fire the last round as opposed to reacting after you realize that was the last round is all the time in the world.
HEADSHOTS aren't as important as slowing an attacker down - if you miss a headshot the attacker is still coming at you fast. Slow 'em down first, then get the kill shot.
HAND-TO-HAND COMBAT only in small numbers - There's no way in the world to take down 20+ concurrent attackers without letting one touch you.
Second, KNOW YOUR AMMO COUNT. The last bullet is the most important, because you have to know that as you squeeze the last round you must take flight, rely on a backup, or get ready to reload. Reacting as you fire the last round as opposed to reacting after you realize that was the last round is all the time in the world.
HEADSHOTS aren't as important as slowing an attacker down - if you miss a headshot the attacker is still coming at you fast. Slow 'em down first, then get the kill shot.
HAND-TO-HAND COMBAT only in small numbers - There's no way in the world to take down 20+ concurrent attackers without letting one touch you.