How to avoid someone?

I have a classmate in college, we were friendly for a while but she only ever talks to me when we share a class, and when she wants answer for homeowork/project ect. If we aren't in the same class we're practically strangers. I want to distance myself from her, but she's how I would explain as fake nice, but, at least to me, she's irritating. Regardless, we're in the same class once again and she's following me around, and I need advice on how to get rid of her. I want her to stop following me, but I struggle with confrontation and I don't really have a good reason to push her away, she hasn't done exactly done anything big, more like little things. Please help.