Six fundamentals first. Then turn them into a case you can actually use.
Every argument has three parts. The claim is the position. The warrant is the reasoning that makes the claim true. The impact is why anyone should care.
"Corporate political donations corrupt democracy" is a claim with no warrant. The complete version: "Corporate donations corrupt democracy because officials demonstrably vote with donor interests over voter interests, so representative democracy stops representing the median citizen."
Judges decide rounds by weighing competing impacts on four axes. Magnitude is how big. Probability is how likely. Timeframe is how soon. Reversibility is whether it can be undone.
A small certain harm outweighs a large speculative one. An irreversible harm outweighs a reversible one of equal size. A high-probability high-magnitude impact dominates everything.
Five ways to attack an opponent's argument, in rough order of strength. Link attack: their argument doesn't connect to the world. Warrant attack: their reasoning fails on its own terms. Impact attack: even if true, the harm is small or speculative. Mitigation: yes, but less. Turn: their argument actually helps your side.
The strongest move is the turn. Prove their argument cuts against them and you've taken an entire contention off the flow with one move.
Judges flow rounds in real time on paper. If they can't track which argument you're on, they can't write the ballot in your favor. Signpost like a wayfinding system: "I'll address three of Opp's contentions. First, economic harm. Second, civil liberties. Third, enforcement cost."
The single biggest gap between novice and varsity debaters is signposting.
Cross-ex, crossfire, and POIs are shared airtime. The goal isn't to win the exchange; it's to plant ammunition for your next speech. The best questions aren't questions. They're concessions you want on the record.
"Would you agree that your evidence is global, not localized?" beats "Why do you think this matters?" Never ask why. Why hands them a free 45-second speech.
Two people can make the same arguments and only one of them sounds like they should win. Register is the difference. Strong delivery uses clean signposting, direct address, real numbers over abstraction, and one memorable line per speech.
Weak delivery hides the claim behind a long preface, packs the speech into a wall of words, or name-drops ideas that do not help prove the case.