For a small business, good management entails quite a bit of detail work regarding staff and stock. A well-managed small business will maintain good practices with routines for cleaning, stocking, and public relations while also keeping track of orders and keeping healthy relationships with vendors.
Good management means controlling costs in order to increase profits. If you keep track of expenses and make sure that you price your product well enough to get a reasonable profit margin, you will be more successful.
There are many possible ways to define this. I would argue that "good management" is any management that can make a profit in the long term. That is, good management is management that runs a company efficiently enough that it can consistently make a profit over a long period of time.