This advice has more to do with serious written criticism, but I like spreading it around.

You should attempt to re-express your target’s position so clearly, vividly, and fairly that your target says, “Thanks, I wish I’d thought of putting it that way."
You should list any points of agreement (especially if they are not matters of general or widespread agreement).
You should mention anything you have learned from your target.
Only then are you permitted to say so much as a word of rebuttal or criticism.

Me quoting Judith Curry quoting Daniel Dennett quoting Anatol Rapaport.

I only ran across this fairly recently, but it makes explicit some vague intuitions I had had before. The few times I consciously have put it into practice so far, I have found it rather time consuming but beneficial. I'm not sure whether I have learned to back away from pointless controversy or how to make points more persuasively, but it has helped me get away from looking at arguments as soldiers in an army kind of thinking.