As a CTO, my default loop is 'First, cycle through all my employees and make sure that I have equipped them to be happy and productive in their jobs. Second, find something to do. If possible, delegate it; if not, do it. Repeat.
Ideas are more important than age.
Just because someone is junior doesn't mean they don't deserve respect and cooperation.
Developing Leaders: What To Do When Your Team Grows Too Big
Christoph Nakazawa's experience being FB manager
Steve Jobs on managing people
The Eng Team Handbook - Developer's guide to management: an open-sourced handbook for leading engineering teams.