Rather hard to do this long distance, but will give it a shot (pun intended)
You need a coach- either someone that can watch and critique, or a video cam so you can self critique.
Take a look thru this video series- Video: Lean About the Types of Pistol Shooting Stances | eHow.com
Focus on your front sight.
Use this pattern to get an idea of why your bullets are hitting in a given sector
Be certain you are using GOOD hearing protection any time you shoot- a lot of new shooters develop a flinch- not so much from recoil as from that NOISE that hurts. And many new shooters focus so much on their grip that they overlook the first part of these videos- where your FEET are located.