For everyone who says it should be obvious, of course hit things from the rear, etc, OP is specifically talking about this:
Yes, people know enough about the terms "flank" and "rear" that they hit things from the side and from the back. But the best way to do it is to be just at the boundary and take a half step over to switch positions, because when you get to primals and raid bosses, doing 90º position changes will require running literally 8y instead of 0.5y.
All attacks get bonus accuracy when hitting from flank or rear. Damage bonuses are specific to certain actions though.