Face pulls are a great exercise at improving scapular upward rotation including the serratus anterior and mid/upper traps.

I like to have the rope or a band a little lower than my face, no lower than chest level. If the attachment point is up too high you'll end up pulling downwards instead of upwards which is motion that you're trying to get.

Note what you end up doing with your head. Avoid a forward head posture. You're looking to pull the rope to your head not bring your head to the rope.

The final key point is to exhibit control during the face pull. You will be aiming to feel the muscles working (posterior shoulder) and not simply using momentum. 

HOW TO

1. Set up with pulley at chest or chin level.
2. Grab the rope with your thumbs facing you, keep the arms up high and pull the rope towards your forehead.
3. As you approach your face, pull the rope apart. You should feel it in your posterior shoulder area not ONLY between your shoulder blades. This isn't a high row.
4. Return to starting position and repeat for 10-15 reps.