Building Custom GPTs That Actually Work: How I Run a 7-Figure Business with AI Assistants

Last year I bought back BestSelf.co and faced an entrepreneur's nightmare: a successful business with no team in place. I needed to keep things running while rebuilding from scratch.

That's when I discovered the power of custom GPTs. These AI tools became my initial support system, handling everything from legal document review to market analysis while I focused on rebuilding the right way.

Now, we're a small but mighty team, and everyone knows how to create and use custom GPTs to multiply their capabilities. Instead of AI replacing humans, we've found the sweet spot: using these tools to handle routine tasks so we can focus on the creative, strategic work that actually moves the business forward.

Here's exactly how we build and use custom GPTs at BestSelf, and how you can do the same.

What Makes Custom GPTs Powerful (And When They Fall Short)

Think of custom GPTs as your personal team of specialists who never sleep, never complain, and come pre-loaded with expertise in their domain.

While regular ChatGPT is like a bright but untrained intern who needs constant guidance, custom GPTs are more like seasoned pros who already know:

1. Deep expertise in their specialty (like a veteran lawyer who knows every contract clause)
2. Your exact preferences and workflows (like a long-time assistant who knows how you think)
3. Industry best practices and common pitfalls (like a consultant who's seen it all)
4. The ability to process vast amounts of data quickly (like having a research team on standby)

The best part? These AI specialists are available 24/7 to support both me and my lean team. Instead of hiring a full department for each business function, I've created custom GPTs that help my team members multiply their capabilities.

But enough theory - let me show you exactly how this works in practice.

My "Oh Shit" Moment at BestSelf

When I bought back BestSelf, I walked into a situation that would make most entrepreneurs panic. The previous owners had let go of the entire team, our SOPs were outdated or missing, and I had a toddler at home (hello, limited time! 👋).

I needed to:

• Rebuild our operation from scratch
• Find and train new team members quickly
• Keep costs low while maintaining quality
• And somehow find time to sleep 😅

Hiring a full team of experts wasn't an option - both financially and because I wanted to stay lean and nimble. That's when I started experimenting with custom GPTs.

Here are the five custom GPTs I built to help run BestSelf (and what they actually do for us):

Five Custom GPTs That Actually Save Time

1. Ad Creative GPT:
   This one's my favorite for scaling our ad creation. I feed it high-performing ads (ours and examples from Foreplay), and it comes up with fresh variations and copy as applied to our products. Instead of spending hours brainstorming new angles, we can come up with multiple creative approaches in minutes. Recently, it helped us develop a whole new ad campaign based on our best-performing Facebook ad.
   
2. Newsletter Brand Voice GPT:
   This GPT is specifically trained on BestSelf's email archives, product catalog, and brand voice. It helps maintain consistency across all our newsletter content while capturing our unique tone and style. Instead of spending hours editing for brand voice, this GPT ensures every email feels authentically "us" from almost the first draft.
   
3. Product Research GPT:
   This is our market research powerhouse. Trained on our product development framework, it analyzes competitor products, customer reviews, and market trends to spot opportunities.
   
4. HR Policy Assistant GPT:
   Running a business without an HR department meant I needed help with employee documentation. This GPT helps draft job descriptions, create employee handbooks, and generate standard HR forms. It's trained on current employment best practices and our company culture, ensuring consistency in all employee-related documentation.
   
5. Data Analysis GPT:
   This GPT transforms raw business data into actionable insights. Fed with our sales data, inventory info and market trends, it generates regular reports and identifies patterns that might take hours to spot manually. It's particularly useful for quick data-driven decisions when you don't have a dedicated analytics team.
   
   The best part? It gets smarter over time as we feed it more data. Last month it spotted a trend in our customer feedback that led to a product improvement we never would have caught manually.
   
6. Legal Compliance GPT:
   When you're running lean, every email to your lawyer means billable hours adding up. This GPT helps me avoid unnecessary legal fees by handling the routine stuff. Since we already had solid agreements from before, it helps ensure new contracts are up to date, flags potential issues, and generates standard agreements. It's like having a legal assistant who can do the first review before we need to involve (and pay) our actual lawyer.

Each of these GPTs solves a specific problem that would typically require either expensive expertise or significant time investment. The key is that they're not trying to fully replace human expertise – they're handling the routine aspects of these tasks so humans can focus on higher-level decisions.

Now that you've seen what's possible, let me show you how to build your own AI expert team.

How to Build Your First Custom GPT

Instead of giving you vague instructions, let me walk you through how I built our Ad Creative GPT. It's the one that's saved us the most time, and the process will work for any type of GPT you want to create.

Step 1: Get Crystal Clear on Your Problem

For us, it was: "How can we create more ad variations without spending hours brainstorming?" I knew we had winning ads, but creating new versions was taking too much time.

What I needed was something that could:

• Understand why our best ads worked
• Generate fresh angles using proven formulas
• Maintain our brand voice
• Save us hours of creative meetings

The more specific you are about your problem, the better your GPT will be. Don't just say "I want help with marketing" - define exactly what you need help with.

Step 2: Load Up Your Knowledge Base

For our Ad Creative GPT, I uploaded everything that makes our advertising unique and effective:

• Brand voice guidelines and creative strategy playbook
• Customer avatars (I'm talking extremely detailed - 8 different personas)
• Our proven copywriting formulas and creative hooks
• Product reviews, press features, and customer testimonials

Pro tip: Think of this like training a new marketing hire. The more context you give them, the better they'll understand your brand and customers. I probably spent 3-4 hours gathering all these materials, but it's the reason our GPT can generate ads that actually sound like us and resonate with our audience.

Step 3: Write Clear Instructions

Let me share both the basic framework and then show you exactly how we use it for our Ad Machine GPT:

First, here's the skeleton every GPT needs:

1. Identity: "You are [specific role] who specializes in [specific outcome]"
2. Mission: "Your purpose is to [main task] by [specific approach]"
3. Non-negotiable behaviors: "You must always [critical behaviors]"
4. Workflow: "For each task, follow these steps: [detailed steps]"

Now, here's how we actually use this for our Ad Machine GPT at BestSelf:

# Identity
You are a world-class ad strategist and copywriter for BestSelf Co., specializing in high-impact ad creation and adaptation. You excel in:
1. Generating innovative, high-converting ad concepts
2. Adapting existing creative ads to align with our brand
3. Analyzing and recreating successful ad formats

Core Mission

Generate innovative ad concepts that combine creativity with conversion-focused messaging
Seamlessly adapt and recreate ads while maintaining proven structures
Proactively audit and refine outputs without requiring intervention

Knowledge Integration

You will use BestSelf's:

* Brand Guidelines
* Creative Strategy Guide (including our Angles Framework)
* Customer Avatars
* Hook Library
* Product Documentation

Workflow
For each ad creation:

Analyze the existing ad structure
Map new product details to proven frameworks
Generate multiple variations
Provide side-by-side comparisons
Suggest performance metrics

Pro tip: Notice how much more detailed this is than most people's GPT instructions. That's intentional - the more specific you are, the better your results will be.

The key is being super specific about what you want. Notice how each instruction builds on the knowledge base we loaded in step 2.

Step 4: Test Before You Build

Here's a crucial step most people skip: Test your instructions in regular ChatGPT before building your custom GPT. It's like a dress rehearsal before the main show.

For our Ad Creative GPT, I tested:

• Analysis of our best-performing ads ("Why does this work?")
• Generation of new variations ("Give me 3 fresh angles on this")
• Different customer avatars ("Rewrite this for our productivity-focused customer")

If something doesn't work quite right, it's way easier to fix now than after you've built the GPT. I probably went through 4-5 rounds of tweaking before I got the outputs I wanted.

Step 5: Build and Refine

Once you've tested everything in ChatGPT, it's time to build your custom GPT. But here's where most people mess up - they think they're done after the initial build.

The real magic happens in the refinement:

• Use it daily for real tasks
• Note where it falls short
• Update instructions and knowledge base as needed
• Keep examples of its best outputs to refine the training

Common Pitfalls (Learn From My Mistakes)

1. Making it Too Broad
   My first version of the Ad Creative GPT tried to handle everything from Facebook ads to email marketing. It was mediocre at everything instead of excellent at one thing. Keep your GPT focused on a specific task.
2. Not Providing Enough Context
   The more specific information you give your GPT, the better it performs. Don't be stingy with your knowledge base materials.

Your Next Steps

Ready to build your first custom GPT? Here's your gameplan:

1. Pick ONE specific task you do repeatedly
2. Gather all relevant documents and examples
3. Write clear instructions using my framework above
4. Test in regular ChatGPT
5. Build and refine

Remember: Your first GPT doesn't need to be perfect. Start small, test quickly, and improve based on real usage. The best custom GPTs evolve over time as you learn what works and what doesn't.

The Future of Custom GPTs

Here's what I've learned running BestSelf with these AI assistants: They're not replacing humans - they're making us more effective. By handling the routine parts of our jobs, they free us up to focus on the creative, strategic work that machines still can't do.

Your turn. What's the one repetitive task that's eating up your time right now? That's where your first custom GPT should start.