Be strongly opinionated, but be comfortable with updating that opinion once you have new information.
Updating is the hard skill to master.
You have to be willing to separate ego from ideas and thoughts and be okay saying I was wrong or my idea/thoughts are no longer valid / the most accurate with this new information.
You also have to be willing to be curious and open to new information and counter points that will invalidate or weaken your opinion.
Be opinionated, debate like hell, but once new information is available be willing and okay with changing and updating your view if it makes sense.