You get friendzoned when you act like a friend, you get a girl when you act like you want her while also being nice.
In other words: MAKE MOVES, talk to her like you want to be more than friends, it doesn't matter what you say, it's how you say it. Breaking the touch barrier is also key. Hug her like you're really into her whenever you see her, if you're daring you could even go for a kiss on the cheek or a compliment, or if you have balls of steel then just go for a kiss. I witnessed a friend of mine just go for the kiss and it worked out great for him. He tells it like this:
"The worst case scenario is you get kicked in the balls. Next worst is getting slapped and next is getting rejected. Or she will like it. Either way, just go for it because nothing is worse than regret."
Girls go back to guys they have had sex with multiple times because of the deep emotional and psychological attachment that forms from losing one's virginity to someone. Not the case for everyone, but absolutely the case with a lot of people, especially girls, ESPECIALLY immature high-school girls.