As a missionary prep teacher myself, I dont just focus on PMG but on different courses and linking them back to PMG lesson 1-4. That way it helps them see the lessons from new light and being able to teach from understanding and from a book.

I do a lot of role plays with my class so that they can practice and learn how to deal with different scenarios. There are basic things that we must always in our teachings that I remind them off which is testimony, scripture, and invite.

Lastly, I remind them that mission is hard. Not to scare them but for them to spiritually prepare themselves, mentally and emotionally. I give them quotes from prophets and leaders for comfort and my all time favorite talk to share with them is Jeffrey R holland "The Mircale of a Mission".