There is much in this character upon which to write. I think that you could concentrate on several traits and examine their role, impact, and evolution over the course of the novel. Initially, I think that the notion of emotional selfishness and the shallowness of emotional depth that often accompanies it would be one area of Gray's traits that should be explored. The idea of living for beauty and for an aesthetically pleasing conception of the world carries with it a self absorbed nature that compels him to use people as means to ends as opposed to ends in their own rights. Dorian's pursuit of an external end of beauty causes him to break hearts, rupture bonds of friendship, and live a life without any sort of moral substantiation. There is little in way of ethical depth that is present. This could also be explored in strong detail and related to historical development in social periods where shallowness has reigned supreme and its implications from it.