There are a few very simple things that are important to remember if you wish to be a good manager.
1. First and foremost - don't be a jerk.
Treat Everyone, from cleaning staff through to executives, with utmost respect. Too many people get a position of "authority" and suddenly look down on other staff who are "lower" in the hierarchy. Not only is this wrong on a human level, it is also a serious strategic error. You have no idea what there connections may be, what influence they may have, or where they may end up being in the next year.
It also means that you should not sabotage "rivals", step on people's heads to advance, steal credit (or even worry about who gets credit at all), or stab people in the back. Unless you are a pirate, none of these tactics are helpful to a career or a healthy workplace.
