When in doubt, empty your magazine. The side with the simplest uniforms wins. If the Platoon Sergeant can see you, so can the enemy. Never stand when you can sit, never sit when you can lie down, never stay awake when you can sleep. The most dangerous thing in the world is a Second Lieutenant with a map and a compass.
Exceptions prove the rule, and destroy the battle plan.
The enemy never watches until you make a mistake. One enemy soldier is never enough, but two is entirely too many. The worse the weather, the more you are required to be out in it. Whenever you have plenty of ammo, you never miss. Whenever you are low on ammo, you can't hit the broad side of a barn.