I think I stole these from Jim Wendler but not sure.
6 pull-ups (palms away from you)
6 neutral grip pull ups( palms facing)
6 chin-ups- palms facing you
No rest between grip changes.
Thats ONE set.
Do 1-4 sets depending on your strength and conditioning levels and your training priority.
Just like every other back movement. Straighten your elbows. Let the back stretch a little bit. Start to pull yourself up by pulling your shoulder blades down your back.