You could look at how the novel represents the tension between tradition and change, between social conventions and the characters' aspiration to break them. The novel was written in 1920 after the shock of the First World War which had shattered certainties and ushered in new anxieties. The Age of Innocence is set in the late nineteenth-century New York society at a time when individuals were beginning to challenge conventions about what was acceptable. Yet, these still held. You could explore how the different characters are divided according to those who, though not without hypocrisy, support traditions (such as Sillerton Jackson, Larry Lefferts and May) and those who challenge them (Ellen). Newland is caught in between as he would like to pursue his love for Ellen, but is unable to do so because he knows that his world woud never approve. As Harold Bloom puts it, "Newland's world centers upon an idea of order, a convention that stifles passion and yet liberates from chaos."