A clear thesis
Reviewers should know what you are arguing by the end of the first page. A thesis is not a topic (“this essay is about inequality”) but a claim someone could disagree with (“a data dividend would do less for inequality than a higher minimum wage”). State it early, and let the rest of the essay defend it.
Honest evidence
Use data and theory to test your claim, not just to decorate it. Cite your sources and the year, prefer primary data to a secondhand figure, and never stretch what the evidence can show. A modest claim that is well supported beats a sweeping claim that is not — and experienced readers notice the difference immediately.
The strongest objection
The fastest way to look like a serious thinker is to take the other side seriously. Find the best argument against your thesis — not a weak version you can knock down — and answer it. Essays that only argue against straw men read as one-sided; essays that engage the strongest objection read as fair and confident.
Prose that carries the argument
Within a 1,500-word limit, clarity is a competitive advantage. Write for an intelligent non-specialist: define a term the first time you use it, explain why a number matters, and make each paragraph do one job. If a sentence does not advance the argument, cut it. The essays that win are almost always the ones that are easiest to follow.