1. You can't manage groups, only individuals.
It's crazy to think that you're managing a group of people, because the "group" is an abstraction that exists only in your mind. Either you're managing the individuals in that group or you're managing the individual who's managing those individuals. Period.
2. You can control or coach, but not both.
Every manager must make a fundamental decision: Is your job to control an employee's behavior or to coach the employee so that the behavior improves? You can't do both because they're mutually exclusive.
3. Hire very slowly but fire very quickly.
Take your time hiring because the cost of a bad new hire is astronomical. By contrast, if somebody isn't working out, treat the situation like surgery. Make the cut quickly so that everyone (include the person you fired) can move on.
4. To get loyalty, you must first give it.
Many bosses complain about employees who jump ship. The bosses who were self-aware, though, realized it's unrealistic to ask for employee loyalty unless you, the boss, are willing to take a financial loss in order to keep those employees employed.
5. Too much leadership spoils the team.
You want a team full of leaders, right? Wrong! Most of the time you're better off hiring worker bees than queen bees. Think of it this way: An orchestra consisting of 110 conductors is just a bunch of people waving little sticks.