I have found trigger placement on the trigger effects where the bullet goes.
I have small hands and found that if I keep my finger tight against the side of the gun then allow it to go through the trigger guard and let the finger touch the trigger where it does (closer to the joint in the finger), my shots improved drastically.
This was explained to me that because I kept my finger tight to the gun it did have a way to pull the trigger on an angle making the shots be off centered, keeping the finger this way only allows straight back pulls.

If you pull the trigger with the tip of your finger that usually leaves your finger extra room to pull at an angle. I hope this makes sense, it is easier to just show you then to try and describe it.