I had a chance to go to my gun club today with my G23 and XDM 4.5 9mm. First, I changed the grip insert on the XDM from the smallest to the largest, as I noticed that with the thinner grip I was using the knuckle on my trigger finger as opposed to the pad.
I focused on using the pad of my finger as well as trigger control, mainly pulling straight back on it. The difference was noticeable. At 21 feet, just about everything was in the 9 circle. They ranged from the X to the left side of the 9 circle, so I'm still pulling a little left, but the groups were substantially tighter. It's an outdoor range, and unfortunately it started to rain so I had to cut it short, but the tips everyone provided helped quite a bit. I still have my work cut out for me, but it looks like I'm on the right track. Thanks.