Just a lil'bit more info...the only rule I know (and use) is not to mix font categories. Unfortunately, the only categories I really know are the broadest three: sans, serif and script (don't mean to insult or irritate anyone if I'm not correct).
Although I'll never get caught using Papyrus again, for illustrative purposes would anyone be willing to explain to me the qualities you'd observe about the font in choosing a complement for it? What questions about the known font should I ask myself in order to create a pair? I can't even categorize a font like Papyrus so that means the only rule I know is ineffective to me in that instance.
Thanks everyone in advance for your thoughtful responses!!!