America's Army -> to CS

How to switch to Counter-Strike Source from America's Army

Rule # 1
Never hold down fire. With rifles you want to BARELY burst the gun for 1 or 2 shots, sidestep to dodge, and then burst again. The sidestep allows time for your gun to regain it's accuracy, so then you can fire again, while also dodging.
Rule # 2
Crouching is almost always bad. Crouching makes you slow, and immobile, and the increase in accuracy is not really that helpful. NEVER crouch around corners. STAND to strafe around corners. It makes you faster, a harder target, and allows you to strafe back in if it's not safe.
Rule # 3
Aim for the head for single shots. Aim lower if you spray your gun (aim for the torso/legs).

Basic Rule for Shooting
The majority of your shots you want to be STANDING, NOT MOVING, and in between your bursts, you want to be strafing left and right to avoid enemy fire. Cover helps for strafing.
If you are spraying with a rifle, you generally want to be aiming DOWNWARDS towards their waist. If you are spraying with a SMG, just aim towards the neck/upper torso.

ALWAYS:
Run with your knife or pistol.
Buy a defusal kit.
Cover/Execute the objective.
Help your teammates.
Check every corner and watch your back for any flankers, no matter where you are.
Choose Auto-Assign.

NEVER:
Stay immobile in a long shoot out with an enemy facing you.
Ignore the objective (Unless it proves beneficial in the long run $$$$ if you're being stacked)
Crouch to approach an enemy.
Rush into a mess of enemies, especially when it is unneccesary.
Stack (Join the unfairly advantaged winning team).

Yes, counter-strike source is a terrible, unrealistic game.