Appellate writing is judged by how easily a busy reader can extract and apply the argument.
Front-load. The introduction should state what happened, what is wrong, and what the court should do, in under a page. A reader who understands the case after the first paragraph reads the rest differently.
Headings that argue. Not Standard of Review and Argument, but propositions: the contract’s plain language permits termination without cause. A reader skimming the table of contents should see the whole argument.
One idea per paragraph, announced in the first sentence.
Short sentences. Legal complexity is conveyed by structure, not by sentence length. Subject and verb close together, active voice, and few subordinate clauses.
Facts before law. Judges decide cases about events. A statement of facts that is accurate, chronological and specific does more work than any argument section.
Record citations for every factual assertion. Every one.
Authority used, not stacked. One well-explained controlling case beats six string-cited ones. Explain what the case held and why it governs here.
Address the weakness. Raise the strongest counterargument and answer it. A brief that ignores an obvious problem invites the court to assume there is no answer.
Cut. Then cut again. Length is not thoroughness.