I have noticed that hair styles are a crucial component in making yourself look good, but also to make a whole outfit "work".
As you can see this girl has on a pretty modern but vintage outfit with an over-the-top, long, natural braided style. Long hair and braids could both be classified as "70's", so she has done her research.
If her hair was short and pulled into a bun this outfit would not look right. If your looking to style yourself in a certain look try to work with your hair if you haven't to make your outfit go along with each other. Research the era or genre of style your going for inspiration.