Great little article about what makes a Persuasive Presentation. Are you using these tactics?
Check it out here.
One thing i`ll add here which is something i picked up from Guy Kawasaki is that you should always have little voice which says "so what" whenever you say a fact etc. for Example "our product offers homemakers a faster way to clean dishes <little voice "so what">. This enables homemakers to spend more time tending to children or other duties" yada yada yada. Hopefully you get the idea.