Enjoyment and humour are mostly in the preparation. These effects are not easily produced spontaneously. You don't need to be a natural stand-up comedian to inject enjoyment and humour into a presentation or talk. It's the content that enables it, which is very definitely within your control.
6. Research and studies generally indicate that in presentations you have between 4 - 7 seconds in which to make a positive impact and good opening impression, so make sure you have a good, strong, solid introduction, and rehearse it until it is 'second nature' to you and an action of 'unconscious competence'.
7. Try to build your own credibility in your introduction, and create a safe comfortable environment for your audience, which you