In order to reflect effectively, you should think through your strengths and weaknesses as honestly as possible. In doing so, you should be able to develop a far more self-aware sense of your own development needs and priorities.
Self-reflection can help you think through some of these issues. Your department will have developed tools to help you reflect. They will be able to let you know how you may access these tools.
As you reflect, you may decide that you want to develop some of your skills.