To improve on this shot, I wonder if the fingers actually on the strings would maybe add to the photo. Realizing that you are working with some shutter lag on the Cyber-shot and it might take some practice to get the hand in a specific position. Using shutter priority and setting the slow shutter speed has given you a nice motion feel to the fingers, everyone has different opinions and some may see the hand movement as a distraction. Overall the image feels dark and the details in the wood of the instrument get lost. Using a higher ISO might allow a little more light to add detail and still allow you to capture the movement of the shot. I think you have a nice image, that has some room for improvement. Keep shooting and follow your instincts. Try different settings to see what happens as you change them.