Building a custom GPT agent is like hiring a digital intern who already knows your brand guidelines, your Australian target audience, and your specific marketing goals by heart. For Brisbane business owners, this technology allows you to automate repetitive tasks—like drafting social posts or proofreading blog content—while ensuring every output remains consistent with your local brand identity.
Why Custom GPTs Matter for Your Business
Generic AI can often sound a bit 'Americanised' or overly formal. By creating a custom GPT, you can bake in your ABN details, local Brisbane service areas, and specific Australian English spelling preferences. This ensures your AI-generated content resonates with locals and saves your team hours of manual editing.---
Prerequisites: What You’ll Need
Before you start, ensure you have the following ready:- A ChatGPT Plus, Team, or Enterprise subscription (required to create and use Custom GPTs).
- Your Brand Style Guide (PDF or Word doc).
- Examples of your best-performing marketing copy.
- A clear list of the specific tasks you want this agent to perform.
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Step 1: Access the GPT Editor
Log into your ChatGPT account. On the left-hand sidebar, click on "Explore GPTs". In the top right corner of the GPT Store page, you will see a button labelled "+ Create". Click this to open the split-screen GPT builder interface.What you'll see: On the left is the "Create" (chat-based) and "Configure" (manual) panel. On the right is the "Preview" pane where you can test your agent in real-time.
Step 2: Choose Your Creation Method
You have two options: Create (where you chat with the GPT Builder to set it up) or Configure (where you manually enter details). For the best results and total control over your marketing brand, we recommend clicking the Configure tab immediately. This allows you to be precise with your instructions.Step 3: Give Your Agent a Name and Persona
Under the Configure tab, give your GPT a name. Instead of "Marketing Bot," try something specific like "LMG Content Strategist" or "Brisbane Copywriting Pro."Add a brief description. This is what your team will see when they use the tool. Example: "Expert copywriter specialised in Australian SEO and social media content for SMEs."
Step 4: Upload Your Profile Picture
You can upload a custom logo or use DALL-E to generate one. If this is for internal team use, using your company logo helps build a sense of professional integration within your digital toolkit.Step 5: Define the "Instructions" (The Brain)
This is the most critical step. In the Instructions box, you need to define the GPT’s role, tone, and constraints. Copy and adapt this template for your marketing GPT:"You are a senior marketing assistant for [Business Name], located in Brisbane, Australia. Your goal is to help the team draft [Social Media/Emails/Blogs].
Tone: Professional, friendly, and community-focused.
Language: Use Australian English (e.g., 'optimise' not 'optimize', 'colour' not 'color').
Audience: Small business owners in South East Queensland.
Constraints: Never mention US-specific holidays unless asked. Always include a Call to Action (CTA) pointing to our website."
Step 6: Set Up Conversation Starters
These are the buttons users see when they first open the GPT. Create 3-4 specific prompts to help your team get started quickly.- "Draft a Facebook post about our new EOFY sale."
- "Rewrite this product description to be more SEO-friendly."
- "Review this blog post for Australian spelling and brand voice."
Step 7: Upload Knowledge Files
This is where you give your GPT an "unfair advantage." Under the Knowledge section, click Upload files.Attach your brand guidelines, past successful newsletters, and a list of your services. The GPT will reference these documents before generating an answer, ensuring it doesn't hallucinate services you don't actually offer.
Step 8: Select Capabilities
Tick the boxes for the tools your agent needs:- Web Browsing: Essential for researching current Australian market trends or checking competitor sites.
- DALL-E Image Generation: Useful if you want the agent to create social media graphics.
- Code Interpreter: Great if you want the agent to analyse marketing spreadsheets or CSV data from Google Ads.
Step 9: Testing and Iteration
Use the Preview pane on the right to test your agent. Ask it a difficult question, such as: "Write a caption for a local event at South Bank."If the output is too generic, go back to the Instructions box and add more detail (e.g., "Always mention our proximity to the Brisbane River").
Step 10: Save and Publish
Once you are happy, click the Create or Update button in the top right corner. You will have three sharing options:- Only me: Private use.
- Anyone with a link: Best for sharing with your specific marketing team or agency partners.
- Everyone: This makes it public in the GPT Store.
Select "Anyone with a link" for internal business use to maintain privacy of your uploaded brand documents.
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Pro Tips for Marketing GPTs
- The "Anti-Persona": Tell your GPT what not to be. For example: "Do not use corporate jargon or buzzwords like 'synergy' or 'leverage'."
- Specific Local Knowledge: If your business only serves certain Brisbane suburbs (like Paddington, New Farm, or Chermside), list them in the instructions so the AI can mention them naturally.
- Formatting Instructions: Tell the GPT how you want data returned. "Always provide social media posts with 3 relevant hashtags and a link placeholder."
Common Mistakes to Avoid
- Uploading Sensitive Data: While OpenAI has privacy controls, never upload customer databases, passwords, or highly confidential financial documents to a GPT.
- Vague Instructions: "Be a good marketer" is too broad. "Be a direct-response copywriter focused on high-conversion email subject lines" is much better.
- Ignoring the Australian Context: If you don't specify Australian English, the AI will default to American spelling and terminology (like 'sidewalk' instead of 'footpath').
Troubleshooting
- The GPT is ignoring my files: Ensure your files are in a readable format like .pdf, .docx, or .txt. If a file is too large or an image-based PDF, the AI may struggle to read the text.
- Output is too 'robotic': In your instructions, provide a "Voice Sample." Copy and paste a paragraph you wrote yourself and tell the GPT: "This is my natural writing style. Mimic the cadence and vocabulary of this text."
- The GPT is hallucinating: If it makes up facts, toggle off "Web Browsing" or strictly instruct it: "Only answer based on the provided knowledge files. If the answer isn't there, say you don't know."
Next Steps
Now that you've built your first agent, why not create a suite of them? You could have one specifically for Google Ads headlines, another for LinkedIn thought-leadership, and a third for responding to customer reviews.If you need help integrating AI into your broader marketing strategy or want a professional audit of your digital presence, the team at Local Marketing Group is here to help.
Ready to scale your marketing? Contact Local Marketing Group today.