Lincoln Douglas, Public Forum, and Extemporaneous Debate are persuasive speaking events. Your speech must be geared toward the average, non-technical college-graduate-level audience. You do not need to 'dumb it down' for a Reality-TV audience, but if you are talking too fast, or using undefined jargon - even common LD terms like Utilitarianism or Categorical Imperative - you are hurting your chances. And refer to arguments by their substance, not name dropping - not 'My Plato Card' but 'the philosopher-king argument.' And you must be polite to your opponent, no matter how obnoxious they are.

In LD, your value and criterion count - this is how all of your arguments will be judged, as well as any impacts. If you prove horrible war crimes will be committed under your opponent's case, but have conceded the value of real politick and your opponent effectively argues those war crimes will improve the political standing of the perpetrator, then no matter how morally reprehensible the crimes committed, there is no impact under that value. Conceding the value is fine, if you think you can win under theirs, but understand the full ramifications of doing so are not merely saving time for your clever sub-points, but conceding how they will be judged.

In Extempt Debate, you only have at most two minutes - keep your evidence to statistics and use your own arguments - you really don't have enough time for anything else - which is the point. And avoid the temptation to try to fit 5 minutes of speech into a two-minute speech - if you are speaking too fast to take notes, you are by definition saying nothing noteworthy.

For speech events - clarity is the most important part of any speech - not just clarity of speech, but clarity of meaning and clarity of purpose. If you move, move for a purpose. If you speak oddly or with a heavy accent that is barely comprehensible, it still needs to clearly communicate something; the emotions of the phrase we can't understand, at the very least.

Finally, never tell the judge she MUST vote for you - the judge must vote for whom they think won - declaring yourself the winner is generally bad form, no matter how badly you have trounced your opponent. Forcefully argue in your voters or final speech why you think you won, but no mic drop.