Database Design

I have to do a database analysis and upgrade of a company that employs about 50 people. It is a theater company that also has road productions. Is there any tool out there that I could use to help me analyze their needs? I’m not yet looking for a program that would meet their needs yet. Just something that would help me write out and organize for me and them what their needs are, kind of a database design for dummies, but I’m not a dummy and their needs are obviously more sophisticated than that.