…in my opinion it is respectful, intellectually honest, and strategically effective to take, as a default, an approach to others with whom we disagree that follows certain rules of thumb:
- search for common ground as a starting point
- do not start with the assumption that you are correct, but rather examine all points of view for logic and evidence
- try to honestly understand the other side, and address the best version of the arguments and positions you are arguing against
- avoid making negative assumptions about the goals, motivations, and attitudes of your opponents
- when you are confident that your position in the correct (or at least superior) one, your goal should be to gently educate others, not ridicule, pontificate, showboat, or condemn.
- go out of your way to acknowledge legitimate aspects or virtues of the points of view with which you generally disagree (giving the Devil his due).
- freely admit your own error and make appropriate corrections. Avoid the temptation to evade, deny, or minimize your own error.
From a handy list on arguing.