Mentoring is a long term process, so in order to achieve best results, consistency is essential! Keep a schedule, and make sure that meetings occur regularly (once a week is often best). Be sure to communicate when you cannot make a meeting, and remain enthusiastic and professional throughout the mentoring process. Keeping your mentoring consistent will help ensure that you meet your goals, and that your mentoring relationship ends in success.
Go into your mentoring conversation with an idea of what you want to talk about. The mentor and the protégé should both prepare beforehand with questions and points that they want addressed.