A form of exercises that I like to do for shoulders are Isometric. Mostly focusing on the isometric contraction. Grab yourself a 5 lb. dumbbell and try to hold a lateral raise for as long as 1 minute then rep out 10 slow (eccentric) reps. This is a great light weight exercise for those smaller muscles such as the deltoid(s). You'll feel the pump; and as you can tell, it's unreal!! Adds for a good flex sesh too, especially if it's #flexfriday.