I'm right-handed. Every time I shot a target like that, it reminded me to change my grip on the weapon. Looking from above, I have to rotate the gun clockwise in my hand - i.e - put the butt closer to the meat of my thumb.

Mind you, I said "closer to", not "into" the meat of my thumb.

I also have to think about the way I contact the trigger, and concentrate on a straight pull.