It is completely possible to get a girl even if you know her a little bit.
I was at a part on saturday (i wrote a FR about it) and I had known this girl for awhile but it was only a week ago that I started to game her, and I ended up getting her tongue in my mouth. Start back with A1 with some negs but a lot of cocky/funny, I am a big fan of that. Favorite sound bites to include are:
- While she is talking, "Wait a second, just one second...." *pretend to brush something off her cheek* "there, now you look somewhat presentable. continue" *big grin*
- The "WTF" face
- "You know, it normally costs $3 for a girl to touch me...but for you...ill make it $5."
- "Hey, you know whats interesting?!? None of what you just said" *big grin*
Read Magic Bullets as well if you havent, there is a chapter that just gives you short tips to improve your game in a matter of minutes. Because you know these girls, you can feel free to not worry about opening.
Hope that helps, any other questions or clarification just ask.
- Memento
Hope this will work, i mean i know this will work 
hehe..