How to deal with mean roommate

My freshman roommate and I got along too well at the beginning. But by the start of the second semester, she had changed her intended major to mine and arranged a schedule that was very similar to mine so we could hang out more together. I realized then that I needed to start spending more time out of our shared room. I agree with Aunt Bea - just smile and wave when she comes in but then go on with your own business.