After 50 years of doing dscipleship in university evangelism and pastoral ministry I was greatly refreshed by  TRANSFORMING DISCIPLESHIP by Greg Ogden. IV Press. This pastor gets into making the church a reproducing ministry of the Spirit. He links discipling with small groups and shows how it works with him and others.

MENTORING FOR MISSION by Gunter Krallmann( out of print, and  you'll have to search)but worth it! This is by far the best researched collection of Bble verses and application bathed in the life of Jesus and Paul. I went to Amazon and got all they had(2), called Youth With A Mission and no one's heard of it, yet they published it! This is the BEST  by far of all I've read through the years.

 The emphasis is on target:discipling is modeling all you want someone ele to do and reproduce. No sermon will do it. Life on life is the hard fact that Jesus lived with twelve men.  To Make disciples you MODEL the life and ministry of Jesus...and the ministry applications of Paul. Jesus didn't stay for 3 years just to die on the cross. Religious leaders wanted him dead after a few weeks. The 3 plus years were to live the life before them. They were to copy him. Simple. Only one or two seemed to have any formal education. He didn't need the University crowd to change the world, but welcomed them through Paul's life and ministry. Get close enough to Jesus to model what you see and hear. The 12 men and some women were to know His heart, copy him, and then give their lives to lead others to do the same.

The young men I led to Christ or grabbed to disciple, recalled to me years later details of what I said and did in detail on our witnessing and ministry times together!  Some think with a couple hours a week in a Bible study that will do it. It's a vital part, if we teach themHOW TO feed themselves. However unless get into LIFE experiences with them they  rarely reproduce. I do "WIND" with my guys as Jesus did: Witnessing, Intercession, Nurturing and Discipling.  And it takes time over months. His Waylon Moore