When it comes to building a memorable brand, it's all about consistency.
When you're shopping for your favorite cereal or coffee at the grocery store, you want to be able to spot it from a mile away.
The best brands stick in our brains because their presence is defined by the repetition of the same logo, fonts, colors, and images. Once we see them enough, they become instantly recognizable, bringing us a clear sense of reliability and security.
Developing a consistent brand starts with creating a brand style guide.
These branding rule books help graphic designers, marketers, web developers, community managers, and even product packaging departments all stay on the same page, and present a unified vision of the brand to the public.
Think of one of the most recognizable brands of which you're aware. Chances are that you've learned to recognize it because of the consistency across of the messaging -- written or visual -- that brand broadcasts. The same brand colors are reflected across them. The language sounds familiar. It's all very organized and, while not rigid, it's cohesive.
The purpose of the brand style guide, then, is to form and maintain all of those various elements that, when combined, spell out the entire brand as it's recognized.