You have had soome good tips on shooting technique already however...
Let's start... What kind of ammo are you using? Is your barrel leaded?
Start with a clean barrel. I recommend a light film of Break Free CLP... chambers & barrel & everything but the grips outside. Run the BF patch through & then a dry patch... This way any lead or fouling will be on top of the film, easier to clean & clean barels are accurate.
Now we have the housekeeping out of the way, fire off the bench with sand bags, start close & move out. You must know which ammo your gun likes... pick a mild - mid load for practice.
I always bench every load... if it won't group off sand bags, it won't be better off hand.
Depending on your hand size & grip style, you might want to try different grips on the gun. And different hand positions. With small guns, I like to lock the thump of my support hand over my strong hand, but there are other grip styles.
You need to prove your shooting system up close... gradually moving back as your skill improves.
Front sight, front sight, front sight. You can not focus on your target, the front sight & rear sight at once. It's a physcal impossibility. Initially your focus will be on your target... You must bring your focus back to your front sight... the rear sight will be almost in focus on a short barrel revolver & that is good enough as you silouette the front sight in the gap.
Can you see your sights clearly? I recall a detective who needed to reset his bifocals so he could see his front sight... before he shot.