how to get unnervous....
think of them as people, and not goddesses (I had that problem myself before)
remeber that no matter how hot they are, someone out there is tired of their sh!t
they have flaws, just like you and i
have a ice breaker handy. Some common ground in order to talk to them about.
if there are in two, a wingman could prove handy
remember, they LOVE to talk (at least most of them). ask them questions and then ask questions on what their replies are
be confident about yourself.
even using all this advice things might not work out. if it doesn't go on to the next one.
edit: how do you know to get nervous:
when you don't want to give them a bad impression, you get nervous as to what you say.
bah. too long to list