Draw, shift, follow the consequences
Almost every question reduces to: draw the relevant diagram, shift the relevant curve, and say what happens to price, quantity, welfare and whoever is affected. The diagram is not an illustration of your argument — it *is* your argument, and the prose is a description of it.
So revise by drawing from a blank page, not by looking at diagrams in a textbook. A diagram you can recognise is worth nothing; a diagram you can produce, label and shift under time pressure is worth the question.
Evaluation is where the top band lives
- It depends on elasticity. The single most reusable sentence in economics.
- Short run versus long run. Frequently opposite conclusions, and naming that is a mark.
- Who gains and who loses? Distribution, not just efficiency.
- What are the assumptions, and are they plausible here? Perfect information, rational agents, no externalities — attacking the assumption is usually where the top band starts.
- Reach a judgment. An answer that lists both sides and declines to conclude sits below one that commits.
Real examples are marks
A generic answer about 'a tax on a good' scores well below one that names a real policy, a real market, a real figure. Keep a running file of examples as you go through the course and card them — they are the specific detail that separates a competent answer from a good one, and they are trivially forgettable.