How do I talk to a girl I've never met?

I am a junior in high school and I noticed a freshman this year in the hallways that I think is cute. I do not know how to randomly start a conversation because I am too nervous and I don't want to seem creepy. We have no cles together which makes it tougher. My friends are encouraging me to finally make the move, but i'm petrified! How should I go about talking to her?