"I have no special talents. I am only passionately curious. "
- Albert Einstein in a letter to Carl Seelig, March 11, 1952.

1.) The first and most important tenant of any geek culture is simply this: Be passionate.

It doesn't even matter what it is you're passionate about.  Though "geek" is a term inextricably linked with computing, geeks come in more varieties than can be counted.  Artist or engineer, film aficionado or programmer, the common thread among geeks is a passion for something.  That might seem to be an almost all-encompassing parameter for defining a culture, until you take a moment to look around and realize - passion is in short supply these days.