Relax and be friendly. Its really the only thing you can control in the situation.
The rest will be the other people's perceptions which are hard to influence.
I believe anyone that exudes a genuine friendliness and sincerely likes other people are way ahead of the game.
Also, unless you come across negative to a few of the brothers and you express an interest in the organization you usually get a shot out of it.
Oh and be polite
James