After you have detirmined the basic accuracy of your gun, remember that group is a result of consistency. If you do the same thing every time, if the cartridge does the same thing every time, if the gun does the same thing every time and if the wind does the same thing every time, then the successive bullets will strike the same point every time.
Repitition is the key to accuracy. Practice with light loads or small cartridge to drill your hand and arm muscles into the hold and motion you want. You have finer control over the movement of your trigger when using the pad of your finger tip than when using the joint or middle strut of your finger. Hold your hand out with the first finger crooked as if touching a trigger. Assume that you have to move the trigger 1/4 inch to achieve hammer-fall. Now watch how far you have to move your finger to get that 1/4 inch with the pad, compared to how far you have to move your finger to achieve that same movement of the trigger with the joint or middle strut of your finger. Keep the trigger on the center of the pad, as you lose strength when using the very tippy-tip.
When working to get groups in a target environment (bulls-eye,) put pressure on the trigger when the sights settle on the bull. Hold that pressure when the sights wander off. Increase the pressure when the sights next settle on the bull. Eventually, the gun will fire, and will do so while the sights are settled. If you find yourself starting to wander more than you are settling, then back off, drop the gun off target, relax and count a few seconds. Then bring it back on target and start again.
Look at the fit of the stock to your hand. The stock should fill the hollow of your palm and rest your trigger finger pad naturally on the trigger, centered in the vertical curve of the trigger. Build up and/or trim down the stock to get this fit. I had to use pieces and parts from 3 different brands of grips to get my P85 to fit properly. I bought an oversized grip for the Dan Wesson .357 and filed, rasped and sanded until I got that same fit. I put a medallion on the grip of my Colt's BP .36 to get that fit. Now, each of the three comes out of the holster properly fitted to my hand to achieve hits at 7 yards when I point shoot. They also give me consistent groups when I use the sights.
Each of my firearms is capable of greater accuracy (tighter groups) than I am capable of shooting. Once I proved that with bench rest shooting and load development, the rest of it is now up to me. Excuse me now, while I go practice.
That should be worth about $0.02.
Pops