Wait what, this thread wasn't started by 2003?
Just be funny man...and not the, awkward guy funny, genuinely funny. A dash of alcohol goes a long way to get over the nervous bits if that's an issue.
But the problem probably is, that if she isn't feeling ´something´ from the beginning, if there isn´t any kind of tension, it's a lot harder. I always find whatever a girl I really like says hilarious, even if it's completely boring otherwise. And that goes both ways, if you're both in that placce you can talk for hours about absolutely nothing and everything just goes without having to do ANY effort at all.
If you have to go on an interview forum to find a way to get it done...meh, methinks it´s probably not gonna happen. And let me finish off with the standard ´be confident and happy with yourself´ cliché, which couldn´t be more true. But that´s also not something you can easily change, you really have to feel that way.
You are welcome for the most useless advise ever.
But what did you expect, that there is some magical, foolproof formula? Every guy and girl is different, so even if two guys do the exact same thing to the same girl, it probably only would work for one of them in a hypothetical situation.