While 'Cross is all-encompassing, friendly and a heck of a lot of silly don't think there isn't a whole set of 'rules' that define PRO.
While the roadies have them up in lights on the internet, I'm yet to see the CX version clearly documented (perhaps for good reason).
Luckily one of the More Prominent Identities of US Cross has posted up something of a "Do's and Don'ts" to help shine a little light on how to 'look good'.
*Please note that taking any of the "rules" too seriously may affect your ability to simply enjoy cross riding and racing and if this occurs please cease to follow the directions. In fact if that happens please watch the video in this post IMMEDIATELY!