As has been mentioned, nature vs. nurture is important in this story. The major thrust of Shelley's novel is that the creature becomes a monster because Victor and society treat him so badly. The creature repeatedly attempts to make a connection with the human race—which continually rejects him. Are we surprised by this when his own "father" rejects him so completely?
In your paper, I would point out Victor's inability to assume his parental responsibilities. Although too late he realizes that he has done something terrible by creating the creature, he never assumes his responsibility for it. He never tries to train the monster to stay out of sight; he never offers to provide for the creature. A compelling argument is who is the true monster in the story—the creature or Victor?
Had Victor, with all of his learning and knowledge, been able to see beyond the creature's appearance and his own mortification over what he has done in creating life, at least HE could have been the monster's friend, and avoided the heartache everyone in the story suffers, most of all Victor when he loses his loved ones.
My emphasis would be on the creature's gestures of kindness: saving the little girl from drowning; refusing to harm Felix when the young man beats him; and, his insistence that he wanted only what all humans want: love. Even his willlingness to leave the human race with a mate, never to be see again, proves that he is much more human in some ways, while Victor is the more monstrous of the two. In acting as he does, Victor destroys the lives of all those around him, including the creature, and even his own.