Cable upright rows are a good exercise for strengthening your upper back.
Steps
Attach a straight bar to the pulley on the floor. Tighten your abs and stand with your feet shoulder width apart. Grasp the bar with an overhand grip. Your palms will be facing your body and be fairly close to your waist. Next, raise the bar toward your chin. Pause at the top and return the bar to the starting position.
Tips
Keep your body and your wrists straight. Your wrists should even be straight at the top part of this exercise.