Most brand voice guides are filled with abstract concepts like "be authentic" without showing you what that actually looks like. "Professional yet approachable" doesn't help you write an Instagram caption. You need concrete examples that show your voice in action.
Start with 4-6 specific adjectives that describe your voice, tone, and style. Not "professional" (everyone wants that), but "encouraging," "straightforward," "slightly sassy," "warm," or "no-nonsense." These become your voice filter—everything you write should reflect these traits.
Include real examples of your voice in action. Show how you'd write an email subject line, a social media caption, an About page paragraph, and a sales page headline. This gives people a template to follow instead of just concepts to interpret.
Make it accessible and easy to reference. Don't create a 20-page document that lives in a folder somewhere. Create a simple, scannable guide that you can actually use when you're writing content. Consider making it a shared document that anyone helping with your content can access.
Update it regularly as your business and voice evolve. Your brand voice when you're starting out might be different from your voice when you're established. That's OK—just make sure your guide reflects who you are now. Test it with real content and refine your guidelines until they actually help you create better content. Enji's brand voice tool gives you a framework to capture your unique voice and use it consistently across all your content.