Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes.
When disagreeing, please reply to the argument instead of calling names.
Please don't fulminate. Please don't sneer...
Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.
Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something.
Oh, see here's the secret. Lots of people THINK they are always right. Nobody is.
The problem is you can read a lot of books, study a lot of philosophy, practice a lot of debate. None of that will cause you to be right when you are wrong. It will, however, make it easier for you to sell your wrong position to others. It also makes it easier for you to fool yourself and others into believing you're uniquely clever.
> Although I do not suppose that either of us knows anything really beautiful and good, I am better off than he is – for he knows nothing, and thinks he knows. I neither know nor think I know.