The idea behind posing is to create effect and illusion.
NEVER LOOK THE CAMERA STRAIGHT IN THE EYE. The same goes for the audience. Look just above them or a little off to the side. Lift the head a little more. Learn to be more dramatic. Your posing should be approached like a PERFORMANCE.
Contests are shows. It's showbiz, whether you like it or not.
Promoters today are just starting to pick up on this again. Be dramatic, heroic, even slightly arrogant in some of your side and three-quarter poses. Tilting the chin up creates better lighting for the face and the upper tie-in of the TOP of your body.
For instance, on a three-quarter shot, the head looks up at a slight tilt and then over the shoulder – DRAMATICALLY – and it SLENDERIZES the Sternocleido Mastoids of the neck to make your shoulders appear broader.
I repeat: what's going on up there on stage IS drama. Play it up.