Even though this was written by a current Less Wrong poster (hi, pdf23ds!), I don't think it has been posted here: Why and how to debate charitably (pg. 2, comments). (Edit: The original pdf23ds.net site has sadly been lost to entropy – Less Wrong poster MichaelBishop found a repost on commonsenseatheism.com. He also provides this summary version.)

I was linked to this article from a webcomic forum which had a low-key flamewar smouldering in the "Serious Business" section. (I will not link to it here; if you can tell from the description which forum it is, I would thank you not to link it either.) Three things struck me about it:

1. I have been operating under similar rules for years, with great success.
2. The participants in the flamewar on the forum where it was posted were not operating under these rules.
3. Less Wrong posters generally do operate under these rules, at least here.

The list of rules is on pg. 2 - a good example is the rule titled "You cannot read minds":

As soon as you find someone espousing seemingly contradictory positions, you should immediately suspect yourself of being mistaken as to their intent. Even if it seems obvious to you that the person has a certain intent in their message, if you want to engage them, you must respond being open to the possibility that where you see contradictions (or, for that matter, insults), none were intended. While you keep in mind what the person’s contradictory position seems to be, raise your standards some, and ask questions so that the person must state the position more explicitly—this way, you can make sure whether they actually hold it. If you still have problems, keep raising your standards, and asking more specific questions, until the person starts making sense to you.

If part of their position is unclear or ambiguous to you, say that explicitly. Being willing to show uncertainty is an excellent way to defuse the person’s, and your own, defensiveness. It also helps them to more easily understand which aspects of their position they are not making clear enough.

The less their position makes sense to you, the more you should rely on interrogative phrase and the less on declarative. Questions defuse defensiveness and are much more pointed and communicative than statements, because they force you to think more about the person’s arguments, and to really articulate what it about their position you most need clarification on. They help to keep the discussion moving, and help you to stop arguing past each other. Phrase the questions sincerely, and use as much of the person’s own reasoning (putting in the best light) as you can. This requires that you have a pretty good grasp on what the person is arguing—try to understand their position as well as you can. If it’s simply not coherent enough, the case may be hopeless.