You must find a professional speaker who would best suit your domain of expertise. Professional motivational speakers are divided in function of their areas of knowledge and a categorization of these speakers can be easily found by using almost any search engine and typing their names or domains. Secondly, you must inform the professional motivational speaker that you are hiring about the central theme that you want highlighted by his speech. The professional style of a good motivational speaker will subtly insert your theme into his speech and mark the important points of the discussion.