Stand up straight.
Take a band and step on it with one foot to create some tension.
Hold onto the band at the opposite end in your affected hand.
Start with your arm straight down at your side and the thumb pointing outwards.
Raise your arm out to the side, keeping the elbow straight.
Make sure you do not hunch your shoulders, or lean your body as you lift the arm against the resistance.
Stop when your arm reaches the same height as your shoulder.
Control the movement back down to the starting position and repeat.