Your mentor is human, therefore not perfect. It is unrealistic to expect that he/she will fulfill all the demands regarding your career and personal issues, but they can help you identify others who will be better equipped to help in a specific situation.
Have clear and open communication. In this technology-driven society it should be easier to make appointments; by scheduling time with your mentor you guarantee yourself their full attention. Be prepared for your meetings, be on time and have a list of topics that you would like to discuss. Come up with deadlines and keep your mentor up to date with your progress or struggles. If for some reason you need to cancel your meeting please make sure that your mentor receives the message, it will avoid unpleasantness.
Your mentor’s time is precious, do not submit “rough drafts” for input; make sure that your draft is presentable and free of typographical errors.
Accept criticism with grace. Remember, that it is your mentors’ job to evaluate your work and progress objectively. In the same manner you should demonstrate a willingness to consider their advice, and be able to defend your position as mature and as educated as possible if you were still to disagree to their suggestion. Regarding disagreement, direct communication is the best option. Electronic communication can be misinterpreted or uncomfortable.