The reason shooters practice a lot and don’t get better is they are not practicing correctly. “Correctly” means something different depending on the level of their game.
The shooters between levels C and E will need to train mostly on singles, mounting and moving the gun, and shooting the six basic trajectories: left-to-right, right-to-left, crossing, quartering, birds going up, and birds coming down.
As we’ve said, just going to the range and going through the motions will help you get through these classes. But if those shooters practice mounting the gun and the sight pictures at home every day, the journey will be shorter.