I can spot AI-written marketing copy from a mile away. Not because of grammar or structure — those are usually fine. It’s the voice. It all sounds like the same polished-but-soulless corporate narrator. And here’s the thing: that’s not AI’s fault. It’s a prompting problem.

I’ve spent months figuring out how to get AI to actually sound like a specific brand. It takes about 20 minutes of setup, and then it works surprisingly well. Here’s the process.

Step 1: Define Your Voice

Before you can teach AI your voice, you need to articulate it. Answer these questions:

• If your brand were a person, how would they talk? (Casual friend? Trusted advisor? Bold challenger?)
• What 3 adjectives describe your tone? (e.g., confident, witty, direct)
• What do you never sound like? (e.g., corporate, salesy, condescending)
• What words/phrases do you use often?
• What words/phrases do you avoid?

Step 2: Create a Voice Document

Use AI to formalize your voice:

“Help me create a brand voice guide. Our brand is [description]. We want to sound [3 adjectives]. We never sound [3 adjectives to avoid]. Our audience is [audience]. Create: a one-paragraph voice description, 5 ‘we say / we don’t say’ examples, tone guidelines for different content types (social, email, blog, ads), and 3 sample paragraphs in our voice.”

Save this document. You’ll reference it in every AI interaction.

Step 3: The Voice Prompt

Add this to the beginning of every AI conversation:

“You are writing for [brand name]. Our voice is [paste voice description]. Here are examples of our writing style: [paste 2-3 examples of your best content]. Match this tone and style in everything you write. Never use [words/phrases to avoid].”

Pro tip: Custom Instructions

In ChatGPT, use Custom Instructions to set your brand voice permanently. Every conversation starts with your voice guidelines already loaded.

Step 4: Provide Examples

Examples are more powerful than descriptions. Give AI 3-5 samples of your best content:

“Here are examples of our brand voice. Study the tone, sentence structure, word choice, and personality. Then write [new content] in the same style.”

The more examples you provide, the better AI matches your voice.

Step 5: Iterate and Correct

AI won’t nail your voice on the first try. Use correction prompts:

• “Too formal — make it more conversational”
• “We wouldn’t use the word ‘leverage’ — replace with ‘use’”
• “Add more personality — this reads like a textbook”
• “Shorter sentences. We write punchy, not academic.”
• “This sounds like every other brand. Make it sound like us.”

Each correction teaches AI what you want. After 3-4 rounds, the output gets noticeably better.

Voice Consistency Across Content Types

Your voice should flex, not break, across formats:

Blog posts

Full voice expression. Longer sentences are okay. Personality shines through.

Social media

Punchier version of your voice. Shorter. More hooks. Same personality, compressed.

Email

Warmer version. More personal. Like writing to one person, not broadcasting.

Ad copy

Most distilled version. Every word earns its place. Voice comes through in word choice, not length.

Create a prompt for each:

“Write a [content type] about [topic] in our brand voice. For [content type], our voice is [slightly adjusted description for this format].”

Common Voice Mistakes

1. Being too vague — “professional but friendly” describes every brand. I’ve reviewed dozens of brand voice docs and this is the #1 problem. Be specific or don’t bother.
2. Inconsistency — your blog sounds different from your emails. Use the same voice document everywhere.
3. Copying another brand — inspired by is fine. Copying is not. Your voice should be yours.
4. Ignoring your audience — your voice should resonate with who you’re talking to, not just who you are.
5. Not updating — brands evolve. Review your voice guide every 6 months.

The Test

Read your AI-generated content out loud. Does it sound like your brand? Would your audience recognize it as yours without seeing the logo? If yes, your voice training is working. If it sounds like it could be from any company, keep refining.

Related reading: Why Most AI-Generated Content Fails — And How to Fix It · 15 ChatGPT Prompts for Content Marketers · ChatGPT vs Claude for Marketing Copy — Honest Comparison

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