Correct your mistake as soon as you have found it.
Knowledge of the enemy's dispositions can only be obtained from other men.
Opportunities increase as they are taken.
If the enemy leaves a door open, you must rush in.
When you know both yourself as well as your competition, you are never in danger. To know yourself and not others, gives you half a chance of winning. Knowing neither yourself or your competition puts you in a position to lose.
Sweat more during peace: bleed less during war