Jack Spade's words of brand wisdom (From some semi-recent issue of Fast Company someone snagged from my office and never returned) :

1. The bigger you get, the smaller you should act.
Never, ever start thinking like a big company. Otherwise, you become corporate, and there's no interest in that.

2. Never believe anything you have done is successful.
Challenge it every second, every day.

3. Brand consistency is overrated.
The brand doesn't have to look the same, but it has to feel the same. An element of newness and surprise is important for any brand.

4. Brands should have some mystery.
Customers should never understand the whole picture of a brand.

5. Your people are your product.
They are the vehicle through which everything happens, and they define what you put out.

It probably isn't the sort of thing being taught in most business schools. On the contrary, if the subject is even addressed, I would be willing to bet that in most cases, the exact opposite is still being preached as gospel: Brands have to be consistent. Capitalize on your successes. Brands should be crystal clear. Yadayadayada.

The truth is that there is no cookie-cutter methodology. All you can do is build up your toolbox with old and new ideas, with conventional and unconventional wisdom... and learn how to use the right tools in the right circumstances in the right way. The rest is just about inspiration, vision, and fun.