Try make fine adjustments to your shooting. If your hits are causing the target to go down when hit, you are hitting the top of the clay. If it breaks up, you got it in the tail. Left, you hit the right side, right, you hit the left side. I wouldn't over analyze either. Make sure you are doing something consistently before you try to correct. Also don't aim it like a rifle, point it and concentrate on the target. This is where the adjustable comb others mentioned will come into play. If it is fitting you right, you should be able to close your eyes, mount the gun, and when you open your eyes you should be looking straight down the rib or making a figure 8 if it has two beads.
Also on trap, try to shoot early, as the longer you wait, the target transitions. Early it is rising, wait a bit and it is flat, wait a little longer and it is going down. By shooting early, you will always have a rising target. If you wait too long you will tend to miss over it as when you pull the trigger it has stopped rising and may in fact be dropping.
