I'm finding a lot of good stuff in section 50.
When the word is preached by the spirit of truth and received in that same spirit, both understand one another, and both are edified and rejoice together. (50:21-22) I think this verse is particularly relevant to missionaries and teachers. You MUST teach with the spirit, and if those you are teaching have that spirit as well, they will learn truth.
What can you do to ensure the Spirit will be present? I think one of the best things is simply to pray for it. Keep contention out of the classroom. While it's important to have "pizazz" and make the lessons memorable, the lessons *I* remember are the ones where the Spirit touched me. When the teacher actually testified to us.
"That which is of God is light; and he that receiveth light, and continueth in God, receiveth more light; and that light groweth brighter and brighter until the perfect day. ....I say it that you may know the truth, that you may chase darkness from among you." (50:24-25) I love that imagery. It's not simply to turn away from darkness. This implies a vigorous, active response. Chasing it away. When I think of chasing, I picture myself chasing danger away from my children. I am chasing to protect.
I need to do a better job at chasing darkness away from my children.