I agree with the other guys. Don't shoot groups. When I do, I tend to worry about group size instead of concentrating on each individual arrow. Also, it seems that since you are doing well with very small targets, you are actually still looking at the whole target, but it is small enough that the shot goes well. However on the 3D targets, that won't work. Like Sixgun said, if you pick a small point on the 3D animal, that spot of sunlight or small blemish that you fixate on becomes the whole target, and your small miss still has a good result. You are right, though - it is easier said than done, but with practice and concentration results will improve.