If you don't have any of these, get some. Leadership is an important earmark of success to most people. If you are perceived as a leader, you are more likely to be perceived as being competent. Lectures and Publications - Mention the ones you are most proud of. This shouldn't be an exhaustive list.
People admire people who lecture and publish.
If you have not been active in this area, I advise you to get started. In addition to your competence statements, you should make statements about your service philosophy. Showing contacts that you are very concerned with providing good legal services in a highly professional manner will earn you a higher level of trust. Before you prepare your philosophy statements, you should have prepared your Code of Conduct. If you have not done so, read my articles on The 7 C's of Good Service and Establishing Your Personal Code Of Professional Conduct.