How do i get a girl to like me or get with me...?

well today afterschoool i was with my friends and my othher friend was coming with his cousin which was a girl so i said sup to him and told the girl hi and asked her name she told me but they had to go drop something off what can i tell her if i want her to like me or get with me next time i see her instead of just saying hi what can i tell her so she can like me :/