I think a good manager is someone who, is friendly, approachable, positive attitude and is someone who will not ask anyone to do something they wouldnt do themselves.
I have been a retail manager for over 10yrs and have done many courses here and abroad.
I did a German based management course a few years ago which was based on Body Language and attitude which I think in Management is key.
Also, I find - ensuring you look after your staff by developing them, praising them etc, they will work harder for you. Incentives etc work a treat, ( bottle of wine for the highest sales that week, most appts that week etc)
Good Luck
xx