Look her in the eye's, smile, be sincere but confident. Read the signals and act accordingly and your in.
Or run this through your head from the wonderfully hysterical film Swinger's, an exchange between John Favreau and Vince Vaughn.
https://www.youtube.com/watch?v=oUa2atNxhfg
Trent: "You know what? You're like a big bear with claws, with fangs-"
Sue: "Big f-cking teeth, man."
Trent: "...with big f-cking teeth on you. And she's just like this little bunny, just kind of cowering in the corner-"
Sue: "Shivering!"
Trent: "Yeah, man. You got these claws, and you're staring at these claws, man, and you're thinkin' "how am I supposed to kill this bunny".
Sue: "You're pokin' at it. You're pokin' at it."
Trent: "Yeah, you're not hurting it. You're just gently battin' the bunny around. You know what I mean? The bunny's scared, Mike. The bunny's scared of you."
Sue: "And you got these f-cking claws, man."
Trent: "You got these f-cking claws and these fangs, man. And you're looking at your claws and you're lookin' at your fangs and you're thinkin' to yourself, 'I don't know what to do', man. 'I don't know how to kill the bunny. With this, I don't know how to kill the bunnies', man."
Sue: "You're like a big bear, man."