I found the best way to focus not only visually, but on all aspects of the shot, are to shoot one arrow only. Walk/pull/repeat, but from another location. Run your shot routine completely each time, focusing on each component like you would do blank bailing, and let your subconscious do the aiming. Whether you're hunting or shooting a 3D tournament, there's no need to shoot groups unless you're just checking the consistency of your arrows (and this too is best done one at a time) or are preparing for something like a 300 round.
As for the target...tape a vertical line with something like blue painters tape, or use the tape to create a vertical and horizontal center point on the target and shoot for that.