IMO, it doesn't matter if the model is experianced or a totall newbie, but if there is no communication going on between model and photographer during the shoot, ya ain't gonna get crap.
Let her know what you are looking for, speak. Want a big laughing smile, tell a joke or say something funny. Want sultry, bring the tone of your voice down as if you were speaking to your better half. It brings truth to that ol' saying "Your a tiger, your a tiger", LOL!!!
I have had shoots before were the photographer would just stand there and snap photos. I would ask "what are you looking for" he says "o, what ever". Model looses interest, gets bland, same ole expression and pose.
Any who's, keep the communication open and work together on getting the shot.
Best of luck