What is a brand?
A brand is what you and your people (customers, employees, investors) view as your biggest value proposition. Then, once you figure that out, your brand strategy is how you consistently deliver on that value with each and every thought, action, interaction, and decision you make for your company.
Think of your company like a person. People only do business with people they trust. We only trust people who are clear and consistent in what they say, think, and do. Therefore, your brand strategy is the thing that guarantees everything your company does is clear and consistent. By doing that, you establish trust, and when you establish trust and value, you get sales and lifelong customers.