"Pistol-shooting-chart (Training aid)- How I found out I was tightening my grip while pulling the trigger. Tight groups but always pulled that direction. After using the chart, I could feel what I was doing and corrected it!" this is helpful!
Right to left enough finger on the trigger" you will shoot "to the left" of the target. "too much finger" will cause you to shoot to the "right of the target". "perfect trigger finger" will cause you to " pull straight back" and shoot dead center!