Signs

A sign is a visible stand in for invisible ideas.

For example:

 In our contemporary culture, a baseball cap worn with its bill backwards (which we can see)

stands for

many invisible (which we can't see) such as

rebelliousness, resistance to conformity, edginess, toughness, a laid back, devil-may care attitude.

As an analyst of cultural signs, you zero in on a specific sign that is visible, then make persuasive claims about the invisible ideas that underlie that sign based on evidence from the text.