Stuart Olyott made the following points:
1) Reflect on when you last switched off
2) Learn communication skills
3) Be expository
4) Use stories
5) Ask questions
6) Keep eye contact
7) Use the spoken language (not the written language)
8) Take care of your voice
9) Remember that less means more
10) Be the slave of structure and logic
11) Be in the message
12) Assault the conscience
13) Conquer God before you start (in prayer)
The videos are linked here.