How how should I approach my crush without looking like a creep?

So, there's this girl in my school (I'll call her Ms.14F in this post) and I like her. on a scale of one to ten, I'd rate Ms.14F a solid 8.5. She's bubbly, shares a few of my interests, and something else i cant quite put my finger on. anyway, The one problem is i only share once class with her, and I don't even interact with her often. I've probably said something like 20 to 25 words to her the entire time I've known her. I really, Really want to start talking to her more often, but I have no idea how to approach her without looking like a creep/making it obvious/"Giving away my position". In class she's usually sitting around a few friends, but i know them decently well and sliding my way into conversation is no problem. my real problem is how I could talk to her outside of class without making it look like i like her. My main fear is that my sudden drive and persistence to talk to her will give away the fact that I like her. I've been at the school for way too long to use the "Hi, i'm new here" excuse (got deported from another school to this one), but i want to talk to her and hopefully get some outside contact before easter break. any and all help (topics/conversation starters, how to keep things going, etc) would be GREATLY appreciated by anyone.