Like it or not, we all have a brand. How we look, sound and feel to others. Maybe it's crass and commercial to consider it a "brand" so use another word - personality or character - if that makes you more comfortable. We naturally project our brand but there is value in reflecting on what it is to build stronger relationships with others.
Your brand should reflect what you are passionate about - what gets you out of bed every morning. Most of us migrate towards things we are good at and the things we are good at are usually the things we are passionate about. Unless your passion is living off the land, it is also helpful if people are willing to support what you do. If your passion is making snowman and you want others to support your passion, you may need to up your snowman making game and become a snow sculptor.
A successful brand is unique, it stands out among others. As humans, we are innately tribal and seek conformity with those in our community. If we accept membership in a religious, political or other community with externally dictated principles, our brand will be that of the herd. There may be a sense of security and comfort in having your personal brand created by external forces but it stifles creativity and authenticity. Successful brands are unique and authentic.
Can I provide my world with something that no one else offers? What makes me unique? Those are the questions we have to answer to define our brand. Once we know what that is, we can focus our efforts in support of our brand. Clarity of brand provides clarity of action.
What's your brand look, sound and feel like to others?