Brainpicker's "7 Things I Learned in 7 Years of Reading, Writing & Learning" -- particularly liked #1: admit that you don't know.
"Allow yourself the uncomfortable luxury of changing your mind. Cultivate that capacity for “negative capability.” We live in a culture where one of the greatest social disgraces is not having an opinion, so we often form our “opinions” based on superficial impressions or the borrowed ideas of others, without investing the time and thought that cultivating true conviction necessitates. We then go around asserting these donned opinions and clinging to them as anchors to our own reality. It’s enormously disorienting to simply say, “I don’t know.” But it’s infinitely more rewarding to understand than to be right — even if that means changing your mind about a topic, an ideology, or, above all, yourself."