Adding banded tension to your shoulder work is guaranteed to trigger new hypertrophy gains. Just grab a couple of resistance bands and wedge them under the bench for overhead dumbbell presses.
The key is to lift the dumbbells all the way up to the top and hold them there for a couple of seconds in the contracted position of each rep.
The Shotgun Method allows you to train for both size and symmetry without having to skimp on either. It actually allows you to concentrate on the big lifts without neglecting isolation exercises that address lagging body parts.