I've gotten a few emails from students asking for clarification about how the essays should be structured. So the following are two suggested formats that will work.
Each number represents a paragraph.

Format 1:

1. An introductory paragraph
2. Focus on one character==>What are his/her traits or personality? Give examples.
3. Focus on the second character==>What are his/her traits or personality? Give examples.
4. Optional fourth paragraph==> How the two characters are similar or different. Any further insight that didn't make it into body paragraphs 2 and 3.
5. A conclusion==>Make your final case concerning the similarities and differences of each character.

Format 2:

1. An introductory paragraph
2. Similarities between both characters==>Make sure you also explain what these similarities mean. Why are they important?
3. Differences between both characters==>Make sure you also explain what these differences mean. Why are they important?
4. Optional fourth paragraph==>Explain any further similarities or differences that may not have been addressed earlier in the essay.
5. A conclusion==>Make your final case concerning the similarities and differences of each character.

Any of these 2 formats for the essay will be fine. If you've got any more questions, I'm more than happy to help.
Keep the questions coming!