Writing an essay is bigger than this venue. However, the essay should focus on the idea that in the society in which Ivan lives, ordinary lives are the lives of people who end up in some kind of work camp situation; therefore, ordinary equates to "terrible." He, like most literary characters, accepts what has happened to him and tries to see how, through his acceptance his life might be improved. You should choose the actions which are ordinary, which are terrible, and which show that his attitude has changed. Once his attitude changes, there is no question that his life will change in small ways.