Using either a pronated or neutral grip, pull yourself up until your upper chest touches the bar. Your chest should be puffed out and your elbows pulled down and back – no rounded shoulders or sunken chests allowed.
Before you begin the descent, squeeze your lats, brace your core, contract your glutes, and begin to lean back as you slowly push yourself away from the bar. Use a controlled eccentric and continue to lean back as far as you can the whole way down.
Your torso should be at approximately 45 degrees to the floor. At the bottom, return your torso to an upright position and repeat for the desired reps.
Strive to keep your torso as straight as possible throughout the set. I recommend dorsiflexing the ankles to help lock the lower body into position. If you do these correctly, they'll not only smoke your upper back and lats but fry your core as well.