Imagine you somehow managed to go out with a beautiful sexy girl.
That girl may have a great personality because you did conviced her to go to a date with you with the same charm that fixed you up with all the other dates that you had until this one. But this time is different. she is really hot and you not use to it so much. its not your average looking girl that you take out most of the times. You are starting to feel nervous because you are not sure can sustain a whole date with her without it becoming occurred and not flowing.
They always say, be yourself and everything will be ok. But what if being yourself is the one thing that will crash this date ? ;) what im suggesting here is to pretend that this girl is one of your average looking friend or colleague from work, she can be a cute one but It has to be a girl that you are comfortable talking with her about everything without feeling too ashame or needy. you need to really put a shell on that hot girl you are dating and forget about the fact that she is hot, this is the only way.
If you do it for a couple of times at the start of the relationship with that hot girl she may start to grow on you and you will start feeling natural even with her ! the same way that you use to feel near your friends. Because its really is no such a big deal right? a beautiful woman is just a human being. If she feel that the person who is talking with her give her respect and talk with her like she is her best friend she will like him like every other human being would.