Some general principles for approaching or responding members of cults:-

1.  Genuine love.
2.  Humility.
3.  Recognise lessons to be learned from the cultist.
4.  Knowledge of the teachings of the cult.
5.  Positive testimony to the truth of God’s Word.
6.  Face the question of the source of our authority.
7.  Present the evidence for the major doctrines of the Christian faith.
8.  Follow up contacts.
9.  Keep on praying.

(A.A. Hoekema, The Four Major Cults)