Thanks Kaj, this is my favourite article on LessWrong at the moment. I have plenty to learn.

Most valuable to me at the moment:

Before you stake your argument on a point, ask yourself in advance what you would say if that point were decisively refuted. If you wouldn't actually change your mind, search for a point that you find more convincing. (Is That Your True Rejection? at CATO Unbound)

In discussions, presume the kinds of conditions that are the least convenient for your argument. (The Least Convenient Possible World)

If people are trying to figure out the truth, don't mistake their opinions about facts for statements of values. (Levels of communication)

Only pass on ideas that you've verified yourself. (Problematic, since any given individual can only verify a tiny fraction of all of their beliefs.) (The ethic of hand-washing)

Explicitly separate “individual impressions” (impressions based only on evidence you've verified yourself) from “beliefs” (which include evidence from others’ impressions). (Naming beliefs)

Leave the other person a line of retreat in all directions, avoiding pressures that might wedge them towards either your ideas or their own. (The ethic of hand-washing) Encourage people to present the strongest cases they can against their own ideas. (comment, Carl Shulman)