Perform the combo Drill (removes armor), then a Level 3 green charged shot (stuns), and finish with an Adrenaline Rush.
Easier headshots
If enemies are dodging headshots, perform an uppercut, then shoot them in the head while they are in the air. Note: Use Mondo-vision to make this easier.
Removing dodge cool down
Aim your gun to interrupt the final dodge roll. Repeat this to dodge indefinitely.
Removing heal cool down
Activate the Adrenaline Rush stance (even if there is no blood in your inventory) to interrupt the heal recovery animation.
Using corners
Move around a corner when an enemy attacks, then dodge at the last moment. Since the corner is a barrier, you will execute a Counter Shot and kill all enemies.