Should be your first stop, though it won't have everything you're looking for. Particularly good for people and broad trends (spring break, fast food, Girl Scouts). Also available online, but it's harder to browse.
Use the "Thematic Outline" in the front of the first volume to browse for ideas that might relate to our topic. Some examples: G.I. Joe, Playboy, Gender Stereotypes, Hair, Clothing. Also available online -- but harder to browse.
An excellent source for any clothing or fashion-related topic. Talks about specific designers (Coco Chanel, Gucci, etc.) and major fashion trends in the 20th century.