Before anyone can give you any meaningful advice, you need to tell us:
What type or types of handguns you are shooting.
What distance and type of target you are shooting at.
What the specific nature of the problem is.
If accuracy is the problem, then what sight picture are you using, and what stance you are using.
How much practice have you done? Tried shooting from a benchrest to see the accuracy of the pistol?
The more we know, the more we may be able to help.