I use a square mirror to check alignment. Bedroom mirror or med cab mirror will do. I position my right eye centered (righthanders) to far left of mirror border. . Then move into stance. Making sure cue is directly below right eye and in line with mirror border. also. Like aiming a rifle with right eye. At times I'll drift nose over cue or to left too far. This assumes one has a proper stance to swing cue back and forth. I'm strictly a Ghost ball player.
In actual play I drop the cue inline with CB and OB and then settle. All in one motion.
In actual play I drop the cue inline with CB and OB and then settle. All in one motion.