Not sure if this a mentoring program for a company or if you are starting a business as a coach/mentor for hire. In my experience, you have to ask GREAT questions and then listen, listen, listen. When working 1-on-1, we (the coach), typically have an agenda or program we want to follow, but one size never fits all.
#1 Come up with some leading and probing questions that will get your mentee to talk. No single answer questions allowed.
#2 Learn to be a good listener and pick up on clues on what they are saying to guide you to the next topic of discussion.
#3 Repeat back what you heard them say and ask "is this what you are saying?"
# If you are a coach, give them assurance that you can help them or be honest and say that you cannot.
When I started coaching, I learned that being a good listener is a skill, and it is what will make a mentoring program go smoothly. Remember, it is not about you, it is all about them!
If you need more guidance or some good questions to ask your mentees, please feel free to call!