Courtesy of Dave at HtStW, here is a useful checklist of things to consider in a presentation, if you are not Jon Stewart!  I have edited severely and if you want the meat head over to Dave’s excellent site.

1. Do your homework. Know your subject extremely well. 
2. Give ’em lots of new stuff. 
3. Make sure your information is practical and useful.
4. No bullet point slides
5. Go with the flow. In a small group, if they’re really engaged, my objective is to turn the presentation into a group conversation
6. Use multimedia
7. Speak enthusiastically and passionately
8. Tell stories

Source: How to Save the World

I have done enough of this to know that you have to consider all these elements, and remember a presentation is not the same as a business case back at work.