I posted about 3 ways to spot logical fallacies and 7 deadly logical sins on Source of Insight. These posts are a distillation of some of my lessons learned from Jay Heinrichs, author of Thank You for Arguing: What Aristotle, Lincoln, and Homer Simpson Can Teach Us About the Art of Persuasion .
If you know how to spot logical flaws, you can avoid bad information, protect yourself from bad advice, and improve your own logical arguments. In the rules of rhetoric, your logic doesn't have to be right. You simply have to be influential. Of course, if your audience realizes you are wrong, you lose your ethos (character) influence. In logical debates however, the rules are strict. If you get your logic wrong, the shows over.