Not sure what training you've gone to or what videos you've watched but bad instruction very rarely produces good results.
If you are confused about what to practice, I would suggest you start with James Yeager's Shooting Missology DVD.
Eliminating the practice of bad techniques is just as important as practicing good techniques.
Stay with it. It isn't rocket science--after all, look at the people in this hobby
I maybe should have used purple for part of my first post. Truth is none of the "correct or appropriate" stances/grip has helped my shooting accuracy. They may have helped with other things but not "accuracy" in and of itself. This basically supports Hemingway's assertion that sight alignment and trigger control are the two most important "fundamentals". Really no surprise there.
My carpel tunnel comment needs no purple. My right hand and fingers hurt. You try not jerking the trigger, and yes I do think it is becoming a problem for me.
I still do not completely discount grip, stance, etc. Because it facilitates comfort and the ability to align the sights and properly press the trigger. I do agree that finding a comfortable way to hold the handgun can vary from person to person.
All of my guns with fixed sights shoot fine for me if I do my part. Only thing that throws me off if that I have to cover the target with the front sight. Not really a problem for a fighting gun but not what I want for punching paper.
I did recently sight in a revolver with those dreaded adjustable sights. I had to push the rear sight pretty far off center to the left. Enough that it has me questioning what I have done. But I was easily hitting a 2" stick and see target dot offhand at 15 yards the other day. That does not seem that bad. Wonder if another INGOer would volunteer to shoot my gun for a while to see if it is me (and my aching hand) or maybe the sights were just off a bit?