Something I remember reading about from Navy SEALs on this topic was that they'd start out slow. Walk from one position to another shooting. Speed up your walk as you adjust to being able to shoot on the move, until you're able to do it at a run. Another thing is your targets. Make your targets "person sized", one target and at a set distance at first. Again, add targets and varied distances as your skill set improves. Then, once you're able to hit at a run on multiple targets at multiple distances, shrink the target size. Make the target a person, but make the "score area" a sheet of paper, or an old set of goggles, or a 3"x5" card attached to the target.
Then, you can always add stress to the workout. Instead of just starting from A and moving to B, start at the opposing start station, run across the field to your start station, THEN engage in your drill. Gets the heart pumping, simulating in-game adrenaline.