The most important thing a soldier can do in a firefight

Pull the trigger.

Get off that first shot, or six-round burst if you're carrying a machine gun or a squad automatic weapon or manning a machine gun on a vehicle.

Pull the trigger.

You might think that is self-evident, but it is not. You can train and train, go through qualification on rifle and machine gun ranges, participate in live fire exercises in which you shoot the pop up targets or stand-in targets for buildings. You can do all those things and get awards for marksmanship, but that does not mean you will automatically pull the trigger when confronted with a real target who wants to kill you or when hidden bad guys open fire. 

You must do the right thing.

Locate the enemy and place fire upon him.

Pull the trigger.