Every once and a while there is a ToriAgent Poll Thread. The applicants post the applications with refferrals, reason you would like to become one, etc,.
This was the most recent one: http://forums.toribash.com/showthread.php?t=39588 & http://forums.toribash.com/showthread.php?t=40884

GameKeepers, from what I have heard/experienced, are picked by tournament consistency and quality.

Promo-Team members are hand-picked from the members in it, they will take you under their wing and see if you do a goo enough job doing whatever we tell you to do.