Its been pretty well covered from top to bottom in one way or another. After reading everything a few things I would like to point out. 1st is your eye dominance, are you right handed and right eye dominant? I bring this up because I was a right handed shooter and after being injured in Iraq I had my right hand amputated. After I started going to the range and being dismayed by the results I got a tip that instantly made my grouping get better. I am right eye dominant but now shooting left handed and by putting just a SLIGHT "gangster tilt" I.E. Turning the gun to the right the sight were now inline with my dominant eye. Front sight, is key as well. Another trick I found that has helped is using the top of the sight, not the line or dot on your sights but the actual top of the post. If you are still shooting left and are right handed the pistol Correction chart says that you are now using too little trigger finger. Of course practice, dry fire strength and practice are all key as well but have been covered and will not beat a dead horse anymore. FWIW I am shooting a Glock23 and find it to be a great pistol, since my injury I have had to relearn the basics and done most of my shooting with the 23. One last note as far as .22's go since you have a glock I picked up an ISSC m22 its a .22 glock look alike. While it is hammer fed and does have a safety the feel and trigger are about as close to Glock as youre going to get. Its a bit picky with ammo but still way cheaper than .40, it works for me. Well thats my 2cents worth happy shooting