Stick to the plan. Anticipate, don't improvise. Trust no one. Never yield an advantage. Fight only the battle you're paid to fight. Forbid empathy. Empathy is weakness. Weakness is vulnerability. Each and every step of the way, ask yourself, "What's in it for me?"
"It's a dog-eat-dog world." To reuse the apt cliché. "Every man for himself." "Kill or be killed." "Survival of the fittest." Isn't it all just human nature? Of those who like to put their faith in mankind's inherent goodness, I have to ask, based on what, exactly?