If your Shoulder Day consist of shoulder presses, front dumbbell raises and rear delt flys on the pec machine, you could be going at it all wrong. (weckmethod.com)
I suggest you add in inverted rows and a dumbbell back exercise, like a dumbbell rear delt raise. (fitnessdoctrine.com)
You can also work with this by moving your body under the weight as you come to the top, which helps put tension onto the lateral and rear delts as well. (fitstep.com)