If you do not have one, write one. Be sure it is clear, concise and fits on one page. If your talents do not include writing, jot down all the facts you want your biography to contain and have someone whose writing skills you are confident with write it for you. Include only the number an application asks for, and be sure they are labeled and describe exactly the way the application requires them to be. Make sure they are professional looking.
Jurors are notorious for their bias against poor slides.
For specific information about taking slides of your booth display, please refer to Ruth Pinkus' June 1997 Michigan State Report. Make copies of everything. Often applications will be carbonless forms with a separate copy for you to keep. If they are not, make copies of them, even if it means going to the library or copy center to have it done. Limit special requests.