How unique does my topic have to be?

It would be hard to find a topic that's truly original. What makes some essays feel more unique than others is how you write about your subject. If you use vivid, specific language and stay away from clichés and vague abstractions, your essay will probably be enjoyable to read and represent you well. What matters most is that it be well-written—the quality of one's writing and one's thinking are closely related. If you're able to make the subject interesting, you've likely uncovered some new insight, and thus revealed the uniqueness of your perspective.