It's very hard to describe.
Look at the beginning of this video
http://www.youtube.com/watch?v=e2PdKBCNVbE
I would advice you to pay attention to other layers of communication :
-constant physical escalation
-eye contact
-lower the voice and let it's depth come out
-forget about any logical content whatsoever, you can say anything and create attraction. don't get invested into your point of view when it's not the case, you are not there to do a debate
-when you talk to her, pay attention to her voice, eyes, body language - not only words
-allow spaces of silence if they are natural, you don't need to talk non stop