Here are three great tips from the book, The Everything Coaching and Mentoring Book:

• Coaches do not motivate their employees; they inspire them to motivate themselves.  This is best accomplished by allowing employees to see clearly where they stand in the organization versus where they want to be in their careers.  That is, what are their self-interests versus what the company can offer them.
• A mentor always exercises the power of suggestion. That is, wise mentors offer up plenty of suggestions to their mentees. They pose alternatives.  But they refrain, as much as possible, from telling their mentees what to do.
• Mentoring is all about sharing experiences.  It is about mentors imparting the multiple lessons that they’ve learned to their mentees and helping them better navigate through their own careers.  By absorbing these lessons–of mentors’ mistakes and successes–mentees are better prepared to move forward with knowledge and confidence.