Treating themes as separate silos
Students often write a DBQ or LEQ that addresses only one theme when the prompt rewards complexity from multiple themes. The Reformation is CID, but it is also SOP (princes vs. pope), NEI (religious identity), and ECD (Church wealth). Always ask which other themes are present.
Confusing SCD with NEI
Social organization (SCD) is about class, gender, and family structure. National and European identity (NEI) is about how people define collective belonging. Antisemitism in 19th-century Europe is NEI (exclusion from national identity) and SCD (social marginalization), but they are not the same argument.
Using TSI as a list of inventions instead of an argument
Naming the steam engine, railroads, and electricity is not a TSI argument. The argument is about how those innovations changed European society, who benefited, who was harmed, and what consequences were unintended. Always push past the invention to its effects.
Forgetting that ECD includes ideology, not just economics
ECD covers mercantilism, laissez-faire liberalism, Marxism, and Keynesianism as economic ideas, not just trade data and factory output. When a prompt asks about responses to industrialization or the Great Depression, the ideological debate is part of the ECD argument.
Treating national identity as natural or inevitable
NEI requires you to analyze how national identity was constructed through literature, education, war, and state policy. Saying 'Germans naturally wanted unification' misses the point. Bismarck, Romantic nationalism, and the Wars of Unification were deliberate processes of identity construction.