Below is the link to a sermon from Renovation Church in Atlanta, GA. The topic is specifically about parenting but many of the principles apply to mentoring.
Primarily the idea that if we are not mentoring purposefully then we are mentoring incidentally. Are you mentoring incidentally or are you prayerfully considering a plan to mentor?
Here are what he calls 3 pillars in purposefully parenting, consider how these can inform your mentoring:
1) Informing what the child believes about God
2) Shaping what the child values
3) Instructing the child in how they should live
Let us know how the Lord encourages you through this in your mentoring.