Brand strategy is a broad concept that even branding experts stutter to explain. My favorite definition is:
A long term plan that affects the entire organization, while looking to align visual, interpersonal, and sensorial communications between employees, management, retailers, suppliers, audience, customers and clientele, allowing reallocation of resources in order to hit company predefined sales and market awareness goals.
Brand strategy solves a broad range of internal and external communications problems, such as not knowing who your clients are, how to speak to an audience, how to give your business voice, how to make your business stand out. Brand strategy isn’t just positioning! I made a cool post about it.