Depends if you are giving a Long Brief (Mass brief) or a preflight brief.
A Long Brief needs to impart the theoretical knowledge and handling techniques to a student/s who may or may not have done any pre-reading. Using Powerpoint (or the far superior Mac Keynote!)with videos and whiteboard is the way to go. Remember the handouts at the end.
For a preflight brief, which happens a day or 2 after the long brief (gotta let the knowledge settle into their skulls) just a whiteboard sketch brief with lots of questions does the trick.
For the initial Effects of Controls brief, I found that just talking about it conjured up a mental image of what it would be like for the student. Then when he got into the machine, he expected to see his mental image happen, and when it didn't, it confused him and slowed down his learning. I then made (professionally) a video explaining everything he would see, and this made a huge difference to their rate of soaking up the knowledge.