Find out everything you can about the organization and its membership: How many members does the organization have? What kind of people compose the membership? Men or women only, or both? Young? Middle-aged? All ages?
What kind of organization is it? Business or professional? Service club? Church group? What is its purpose? Its philosophy?
Is it a national or international organization, or is it strictly local?
What are its main activities or projects?
Some of this information might be useful for your speech. Certainly, the speech should reflect some knowledge of the sponsoring organization. There's nothing more flattering to an audience than for a speaker to refer to some worthwhile activity of their organization. For example, ...