Roberto Giobbi, [i wrote:Card College, Volume 2[/i], page 415.]Content
Do the research necessary to speak knowledgeably about the topics raised in your presentation. ... You must know something about the theme of the presentation to give your performance lasting credibility. What would you think of someone who gave an important talk on Japan, for example, when you found out that this person had never been there and barely understood Japanese?
If nothing else, I think the sense of confidence you'll have in your material, knowing that you've done the research, will come across in performance. It's one of those intangible things that I think really does make a difference.