If you want to craft a speech that really hits home, you need to know your audience and their relationship to the topic you're speaking about. Are they predisposed to being receptive or combative about the topic of your speech? What degree of formality are they expecting? What roles do they play in their organizations? What age groups are you speaking to?
This great article on Audience Analysis by Andrew Dlugan goes into a lot of detail about the kinds of questions to ask and answer that can help you hone your message in ways that fit your specific audience's expectations and needs. It's one of a series that explores the topic.