Make sure that your room is spotless. A nice selection of light refreshing foods is good. I'd go with strawberries.
Fondue is nice, if you can get away with having an open flame in your dorm room. Chocolate sause for the strawberries is a nice touch.
A cool chick flick is nice - but don't make it too obvious... unless you have already laid the wood to her. If you have, then I wouldn't bother to create the ambience for her in the first place.