Strafing, at least in first person shooters (FPS) like counterstrike, involves walking sideways. for example left arrow moves your characters to the left. they don't turn towards the left, they just move to the left. Strafing is most effective when you can use the mouse to change your view point. So you would use the mouse to "turn" and you would use the left arrow to move your characters left.

they move left in a sliding motion towards the left...