The longer you track a dove and the more carefully you measure your lead, the greater the chance you'll slow or stop your swing. With no time to aim or measure, you whip the gun past it almost unconsciously and make a perfect hit. Accelerate the gun to catch the bird and pass it. Shoot when you see a crack of daylight between the dove and the blur of the muzzle. You miss doves because you scare them.
Doves see movement very well.
Leaping to your feet as a dove comes into range is sure to make it flare, radically increasing the degree of difficulty on the shot. A dove that never knows you're there is much, much easier to shoot than a bird taking full evasive action. Don't silhouette yourself. Stand in the shadow of a tree. Sit or kneel by a fenceline.