To leverage Yammer effectively, one should optimize their professional appearance by uploading a picture and filling out their profile. They should also build and maintain relationships on Yammer by following others, listening in groups, liking and commenting on posts, and sharing relevant content. Additionally, one can engage others on Yammer by writing engaging posts that are 20% personal and 80% business, include visuals, ask questions, and integrate Yammer into their daily work routine by using the mobile app and allocating time for the platform.