I hung up my wall chart last weekend and started my dry firing practice. I got 25 empties, cut them short so they fit in a shell box, and shoot 4 rounds of trap. I wear my shooting glasses to try and make it as realistic as possible. Dry firing at the wall chart teaches muscle memory and a consistent gun mount, I try to follow the same pre-shot routine and focus on the leading edge of the target.
I'm trying to do it everyday, 100 mounts. Everything that I have read, for every clay shooting discipline, suggests dry firing. I also include eye exercises and visualization (more on that later).