The interviewer is asking this question to see if you are a life-long learner who consistently seeks to gain knowledge to improve the work you do. Businesses and strategies constantly change in fast dynamic environments, so companies must continue to adapt to stay profitable. This means that as the company changes, its workforce needs to adapt too. Try to include improvement activities that relate to the job. A wide variety of activities can be mentioned as positive self-improvement. College courses, self-study, and learning a new software program are good examples.