NEW YORK CLOTHING HELP~~!! What do people wear in NY in winter?

I have always lived in Southern California, where seasons don't really exist and a flannel or a blazer and jeans is the most amount of clothing one needs. I am going to New York at the end of February but have to have my bags packed by Tuesday, I have absolutely no idea how to dress! At most I wear 2 layers of clothing ever. I want to look cute because I am going by myself and am 17 touring colleges, I have a more alternative style, but I just want to be warm. Where can I shop? What should I get? pics greatly welcome.!!