How do I get a girl to like me?

Me and this girl r kinda friends. But I like her more than a friend. People say she doesn't like me because me and my friend use to hate each other. But we r friends now. I make her laugh sometimes, and I'm nice to her. ( when I'm not I'm joking, and it's not even that mean) I've even slimed up a lot. So how do I get her to like me?