PSA: Please do your shoulders a favor and incorporate some rotator cuff specific strengthening into your programming, even if it's only a set every other workout!! . Several things to keep in mind: 1) Work the rotator cuff at varying degrees of shoulder abduction. As you raise your arm higher, you get more teres minor activation in comparison to infraspinatus activation. Both muscles are important in rotator cuff health and are far too often neglected by people performing their external rotation work at higher degrees of shoulder abduction. . 2) Don't forget to work on the subscapularis. It's the BIGGEST of the rotator cuff muscles and is yet often neglected. While many are much more deficient in terms of external rotation strength, don't forget internal rotation strength either. . 3) Gravity works in a downward direction. If you're performing your cuff work with a dumbbell, you need to LIE ON YOUR SIDE. Otherwise, you're just going to look like some noob at the gym that doesn't know what they are doing!