The best way to handle weaknesses is to say what it is and then to say what you are doing to "improve" or "enhance" it. For example: you could say the following "Although I have a tendency to focus intently on my studies, I recently began piano lessons (insert any artistic talent)in an effort to broaden my horizons and relieve stress."
This shows that you are mature enough to recognize your weaknesses and smart enough to do something to improve yourself. However, I caution you. Your interviewer WILL ask you how the lessons are going or they will ask if you can play such and such piece or if you know of such and such artist. Mine did. 😉
