Figure out which qualities they are trying to find in you and focus on them. These may vary with the specific job, but they should be, more or less, consistent. In your answer, you should be cognizant of the type of job you're applying for. Whereas a large corporation might place all their emphasis on the bottom line, a non-profit would measure success not in money but in social impact. You should avoid talking about how you are completely successful. No matter how capable you are, being able to improve will be appealing to interviewer.