Some 15 years ago, Ben Horowitz, then at Netscape wrote an essay, Good Product Manager/Bad Product Manager which details his expectations for his product team. It is a good essay and something all product managers should read. It details not just good, but great attributes for product managers. Many product managers live somewhere between the great product manager and the bad product manager though. For those, this list provides a path for different functions how to move from good to great.
Be sure to check out the original article for good product manager/bad product manager too.