Minorities
-Women
-Africa
-Latin America
Trade
Religions
Big City-States/Kingdoms/etc (eg what happens when leaders want to expand?)
Inventions and Innovations in Technology (what was the motivation behind it? what is it used for?)
Culture
Interactions with the environment (environment is also a key in your guesswork, especially in earlier civilizations. If an environment cannot sustain a population, then what happens? What do people do to modify their environments? The environment tells us a lot about culture, money problems, invaders, government, innovation, etc)
Art and Sciences (again, culture)
Government, organization (and how effective they are)
Revolts and Revolutions (why are people displeased? what is the outcome of a revolt/revolution?)
etc