As an NRA pistol instructor, I agree with ispacpt's comments. A very common problem with new shooters is their failure to follow through. Another issue is a tendency to adjust their grip after each shot. All things that can be corrected if the problem is identified and the shooter works on it. As another poster noted, a good instructor or experienced shooter can often spot these problems. I've even videoed shooters who don't believe they are making the mistakes I've pointed out.

Also, conscientious dry fire can build muscle memory that translates to live fire on the range.