Instagram advertised a post to me that says:

If you can't name the other side's strongest argument, you haven't critically thought through the issue

and

If you can't name your own side's weakest argument, you haven't critically thought through the issue [either]

I've known this but I like seeing it expressed so clearly and explicitly. In addition to stating how one's mind could be changed, I believe these are key ways to be critical of one's positions.