WHAT THE COLLEGE BOARD SAYS:
"The comparative essay focuses on developments across at least two regions or societies. It relates to one of the five major themes in the course, such as state building, interactions between or among cultures, or economic systems. Comparative questions always require an analysis of the reasons for the identified similarities and differences. As in the previous continuity and change over time essay, students may have the opportunity to choose different cases for comparisons from among several options. And, also as in both of the previous essays, a variety of the historical thinking skills (such as argumentation, causation, and synthesis) are evaluated along with comparison."
1. THIS WILL INVOLVE TWO SOCIETIES/REGIONS
The whole point of this essay is to prove that you can analyze two places and point out the similarities and differences.
2. HOW ARE THEY THE SAME? HOW ARE THEY DIFFERENT?
This is not the "Contrast Essay". A problem I always see is that people don't mention the similarities. You focus so much on the differences, that you miss the continuities.
3. YOU MUST EXPLAIN WHY!!! (ANALYZE)
Here's the kicker: YOU MUST EXPLAIN WHY (see above). You can't just say that apples are different than oranges and move on. Why do they have these differences? Why are they similar in this way?