So one thing i have done that has worked for me is call a girl my favorite. Let me explain. I would say something ****y and funny, or neg hit a girl in a playful way, and then i'd say "you know you're my favorite right?" It works with anyone too. My teacher who is about 35 used to not like me, then i started telling her she's my favorite teacher with a joking smile on my face, and she likes me a lot now. I'm one of her favorite students now. I also used this technique on a girl who i have been with for 8 months now. I used to mess up her hair and tell her to shut up and say she was annoying me, in a joking tone of course, and then i would just say "i'm just messing with you, you know you're my favorite right?" and she is completely in love with me (as i am with her). Just thought i'd share that with you all.