If an individual or organization is asking you to speak for them in front of a group of people-ACCEPT. This individual/group thinks you have something to offer to the people they have coming to listen. There is a reason. Perhaps it is to speak in front of colleagues, who will more than likely refer you a potential new client (or are potential new clients themselves), or it is to a whole room of potential new clients. Whatever the circumstance is, you have a room of people who you have done nothing to recruit, with their eyes and ears all focused on YOU. Sell yourself, your business and your field.