From: The Toronto Star (edited)
1. Know your audience
Don't offend them. See the world from their point of view. You need to appeal to their judgement in order to sway them.
2. Listen closely to the other speakers
By listening to every word they say, you’re listening to every mistake they make. Every contradiction and every logical error. That’s the stuff that wins the debate.
3. Be yourself
Don't pretend to be Winston Churchill. By drawing from your own experience, you make the debate a lot more personal and convincing.
4. Research multiple sources
One article isn’t going to provide enough information.
5. Don't argue against everything they say
Your opponents might say something useful. You don’t need to discredit everything they’ve said. Pick your battles. Debating doesn’t mean arguing with everyone about everything.