I would begin by thinking about how the plot unfolds and then work in some insightful comments about character, setting, and theme.
There are five parts to a plot: exposition, rising action, climax, falling action, and resolution.
I. What happens in the beginning (exposition)? What setting, conflicts, and characters are introduced?
II. As the novel moves into the middle section (rising action), how are the characters changing? What new conflicts emerge, or how to conflicts develop? What themes are being developed.
III. What is the most exciting or meaningful part of the novel? This should be the climax. At this point, the major conflicts should be resolved. How are they resolved? How have the characters finally developed?
IV. How is the end (falling action and resolution) presented? Sometimes the writer uses the end to give his reader a different perspective (way of looking at) the story. Does that happen in this novel?
V. How, at the end, is the main theme presented. In other words, what is the writer trying to say about what life and people are like?
You should also consider telling what point of view the story is told from. Why did the writer choose this particular point of view?