“This sounds like AI wrote it” is the worst feedback a marketer can get. The problem isn’t AI — it’s that you haven’t trained it on your brand voice. Here’s how to fix that in 30 minutes.

Step 1: Define Your Voice (If You Haven’t Already)

Before you can train AI, you need to know what your voice actually is. Answer these:

• If your brand were a person, who would it be? (e.g., “A smart friend who explains things simply” vs. “A no-nonsense expert who doesn’t sugarcoat”)
• Three adjectives that describe your tone: (e.g., confident, witty, approachable)
• Words you always use: (e.g., “straightforward,” “no-fluff,” “real talk”)
• Words you never use: (e.g., “synergy,” “leverage,” “circle back”)
• Sentence length preference: Short and punchy? Long and flowing? Mixed?

Step 2: Build Your Voice Prompt

Take your answers and create a system prompt:

“You are a content writer for [brand]. Our voice is [3 adjectives]. We sound like [person/personality]. We use [sentence style]. We always [specific habit — e.g., ‘use real examples,’ ‘address the reader as you’]. We never [specific prohibition — e.g., ‘use corporate jargon,’ ‘start sentences with However’]. Here are 3 examples of content that nails our voice: [paste examples].”

The examples are the most important part. AI learns voice from examples better than from descriptions.

Step 3: Test and Refine

Ask AI to write a short piece (social post, email intro, blog paragraph) using your voice prompt. Compare it to your actual content. Adjust the prompt based on what’s off:

• Too formal? Add: “Write like you’re texting a smart colleague, not writing a business report.”
• Too generic? Add more specific examples and vocabulary preferences.
• Too long? Add: “Keep sentences under 15 words. One idea per paragraph.”

Step 4: Save and Reuse

Save your voice prompt somewhere accessible. Use it as the opening instruction every time you ask AI to write content. In ChatGPT, you can set it as a Custom Instruction so it applies to every conversation.

Common Mistakes

1. Describing voice instead of showing it. “Professional but approachable” means different things to different people. Show AI 3 paragraphs that nail your voice — that’s worth more than 100 words of description.

2. One voice for everything. Your social media voice might be different from your email voice. Create separate prompts for different channels.

3. Never editing AI output. Even with perfect voice training, AI output needs human editing. The voice prompt gets you 80% there. Your editing gets the last 20%.

Quick Overview

Task	Without AI	With AI
First draft	2-3 hours	20-30 min
Research	1-2 hours	15 min
Repurposing	1 hour/piece	10 min/piece

Related reading: Why AI Content Fails · ChatGPT vs Claude for Marketing Copy · AI Content Repurposing

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