Comment by 0xbadcafebee

The lack of communication one doesn't seem like it needs saying, but I've had managers who literally hid information from me, or would keep me out of meetings, on stuff I would eventually have to work on anyway. Don't be that guy. Spread information throughout the team and invite people to meetings even if they don't need to be there (clarifying that they're optional).

Also keep in mind that as a manager, you are a custodian of culture. What you do and don't do will shape your team's culture which will (in part) shape the whole company's culture. So think about how you can develop positive culture (and also, ask!).