Brands have personalities too
Think of a brand like you would a living person... walking around, with a personality of its own. If your brand was a person, how would it act? Quiet and steady, or hyper and intense? Maybe your brand is a bit quirky and unusual? Or loud and brash, making an entrance?
These descriptors will form a major part in shaping the overall look and feel of your brand, so make a note of all the words you think would describe it. This will also shape the tone of voice that you set, through your social media channels, website and marketing literature. When your write something that comes from the brand, think what style they would be speaking in and keep it consistent. Everything should feel like it's coming from the same person.