There are several ways to approach your topic. You could compare/contrast the development of particular literature elements, such as theme, characterization, and symbolism. You could also focus the entire paper on one of these aspects, bringing in more specific. For example, you could focus on the development of the main characters or supporting characters. In this case, your main points should communicate notable traits, motivation, and changes for each character. The most important things to remember are to be consistent with proving your thesis and always use support from the text to verify your perspective.