The others have given some good advice about developing loads but unless your a good shot with a pistol you will still be frustrated with the results.
As you know, pistol shooting is the most difficult of the shooting games.
The slightest quiver, tightening of the grip or pushing against the recoil while the gun is firing will send the shots all over the place.
With this in mind, I advise you to be sitting at a shooting bench, resting your shooting arm on a suitable support as you carefully aim the pistol.
Use a moderately firm grip and do not change it as the gun fires. Do not grip harder or looser while aiming or firing.
Concentrate on the front sight and the target and make a mental note to let the gun "do its thing" without you trying to make any effort to resist or correct it.
If you do these things, it will remove most of the movement or involuntary twitch you may have and the gun will shoot to the same point if the powder/ball/patch load are what the gun "likes".
When you can do this repetitively, then you are ready to work on developing the best powder/ball/patch loads because they will be the determining thing that will show up in the target group.
Note, at this stage you are not trying to get the shots in the center of the bulls eye.
You are trying to make the smallest group regardless of where it's hitting.
After you have found the load combination that produces the best group, write it down so you don't forget it.
Then, you can start trying to adjust the sights to bring the group to the point of aim.
After you have successfully completed this, then, you can start trying to shoot "offhand".
Many of your bad habits will show up again but knowing the gun is capable of shooting small groups you will also know its inaccuracy is due to something wrong that you doing.
With this knowledge you can work on eliminating these errors.
I'm sure if you use this approach you will become a very good shot with a pistol and once learned the knowledge will transfer to any pistol you want to shoot.
Have fun.