Jason Corsello, an analyst with Yankee Group, has just posted some suggestions "in an effort to make vendor briefings more productive and useful for both parties."
I recommend you read the full post but here's a summary of what he has to say:
1) When it comes to the presentation...less is more.
2) Know your audience.
3) KISS (Keep It Simple Stupid).
4) Tell me why you are different.
5) Talk about what makes your customers different.
6) Tell me where you are going to be in 3 years.
7) Passion can not be faked.
If you want your analyst briefings to be effective, following Jason's advice is a good place to start.