An important one:

• Don't use your knowledge of cognitive biases as a fully general counterargument to anyone's position. (Knowing about biases can hurt people)

Others:

• Don't treat your arguments as soldiers fighting for your side.
• Acknowledge when you are personally identifying with your beliefs. This is bad. (Ben Canoscha, Eliezer, Eliezer, Kaj Sotala, Kaj Sotala, Paul Graham, Robin Hanson, Peter de Blanc)
• Distinguish between observation and inference. (Tarski Statements as Rationalist Exercise, HPMoR Ch. 79)

Also, I rather like these.