What are some of the most important Empires that we should look over?
Check out the Cram Chart here! Lists the “hardest-hit” empires for each periodization.
I would also listen to the teachers today as they go over the content. My students on the first two DBQ exams have found it very helpful to have the Fiveable One-Page Cram Charts. You can find this under the resources or follow this link https://fiveable.me/wp-content/uploads/2020/05/AP-World-Cram-Chart.pdf.
Hope this helps!