The trigger is the only part of the gun that’s moving during the aiming process. If you are having trouble with precision pistol aiming, this video with Brian Zins about “aiming through trigger control” will help.
To shoot a red dot in bullseye well, you have to choose: focus either on the target or on the dot. You can’t do both, or go back and forth between the two. Here are techniques from Brian Zins to properly aim a pistol red dot sight
Video: Precision Pistol Tips Part 3―Brian Zins On The Relationship Between Aiming And Trigger Control
Even if you have a perfect grip and can hold perfect sight alignment all day―it only counts when the gun goes bang after you pull the trigger
Trigger finger placement really counts when the shot breaks. Now don’t get me wrong, stance, grip and aiming are important but keep in mind that you can have a perfect grip and hold perfect sight alignment all day long
I have found that many shooters think entirely too much. This is not rocket science, because if it were, I would not be a shooter. Hence, I am not smart enough to shoot badly. When Erich Bujung was the Olympic Pistol Team coach, he always said, “No stinking thinking. The mind is a terrible thing to waste and in Bullseye on the firing line, the mind is just a terrible thing.”
It's all about the fundamentals. Here, 12-time NRA National Pistol Champion Brian Zins explains how a solid foundation in bullseye pistol fundamentals can translate to success in other shooting disciplines.