The rear delts usually get neglected, but this is a pretty easy fix and one you can do at home on a daily basis. The band pull-apart will bring your sad little finger-sized rear delts up to snuff quickly.
You don't need a heavy-duty resistance band because you're going to keep the reps high. Rock bottom rep range is 20, done for 4-5 sets daily.
The true Master Blaster pontificates on shoulder training, adding muscle without putting on fat, BCAA's, whole eggs vs. egg whites, hot Asian chicks, recruiting more motor units, dumb exercises, bar speed, and his inability to love. (We made up that last one.)