How to Build a High-Value Custom GPT From Scratch
11-step guide with prompt template, structure, and file setup
Custom GPTs are one of the most powerful things you can create in today’s AI landscape.
Why? A few key reasons:
Customized Answers - GPTs respond based on your specific needs, tone, and data.
Personal Training - You can train GPTs on your documents or insights, making them smarter than generic ChatGPT.
Team Benefits - Perfect for internal teams; imagine giving your staff a GPT that truly understands your business.
Future Monetization - Soon, OpenAI might offer subscription monetization, turning your GPT into a profitable asset.
Today, I'll guide you step-by-step in creating your own high-value GPT, using a practical example: a "Profitable Business Idea Generator".
Let’s dive in.
Getting Started
You'll Need:
ChatGPT Plus or Enterprise account
An idea for your GPT (e.g., Profitable Business Ideas)
Optional: PDFs, reports, or guides to upload
▸ Step 1: Log Into ChatGPT
Start by logging into your workspace.
Visit chat.openai.com
Use a Plus or Enterprise account
▸ Step 2: Open the GPT Builder
Find your way to the GPT Builder:
From the sidebar, click Explore GPTs
Click the Create button (top-right corner)
You'll see two panels:
Left: Where you type your GPT description
Right: Preview and test your GPT
▸ Step 3 : Write Your First Detailed Prompt
This is where you train your GPT to behave exactly how you want.
First click on create tab if you are not already
Here, you’ll see a split view:
The left side is the chat for building your GPT
The right side is for testing and previewing its replies
Your first message here is the most important this is where you give the GPT all the instructions it needs:
How it should behave
What its role is
What kind of output it should generate
How to use uploaded knowledge files (if any)
How to use user-provided answers from the starter questions
📌 Recommendation:
The more detail you include, the better the results. You don’t need to get it perfect now you can always refine it later. But try to cover everything your GPT should understand and do.
📝 First Prompt Example: Profitable Business Idea Generator
“Title - Profitable Business Idea Generator
You are an expert business strategist with a strong track record of building billion-dollar startups and understanding current business trends, startup mechanics, and funding strategies.
You’ve been provided with 3 documents:
• Top 100 companies with 5-year stock growth
• 100 profitable business ideas
• 2025 emerging industries and market trends
Your goal is to help users generate high-potential business ideas based on their answers to the following:
• Background or expertise
• Budget
• Timeline for monetization
• Preferred industry
Ask those questions first (unless already answered), then analyze and recommend 1–2 business ideas using data from the documents and your own expertise.
Present the response as a concise, professional plan using Boolean bullet points, including:
• Idea Summary
• Target Customer
• Value Proposition
• Required Budget & Timeline
• Go-to-Market Plan
• Monetization Strategy
• Risk & Key Metrics
Use the documents as reference only. Do not blindly rely on themprioritize logic and user fit.”
▸ Step 4: Upload Smart Knowledge Files
Make your GPT smarter with relevant documents.
Go to the Configure tab → Knowledge → Click Upload Files
Upload files related to your GPT’s focus
For example, we upload:
Top 100 companies with 5-year stock growth
100 profitable business ideas
Emerging industries & trends 2025
Tip: Clearly named files help GPT understand and reference data easily.
▸ Step 6 (Optional): Add Starter Questions
Starter questions help your GPT collect useful input from the user—before giving any answers.
Conversation starters are preset questions that appear when someone opens your GPT. These help gather important details upfront so the GPT can give better, more tailored responses.
Note : After adding the first prompt, it automatically includes a few starter questions. You can leave them as they are, but adding your own personalized question is recommended for a more tailored experience.
Why this matters:
Your GPT can’t give accurate results without context.
In this example, our GPT gives profitable business ideas
so we need to understand the
user’s background,
budget, and
preferences first.
Here are 4 questions ll’ll add:
What is your background or professional expertise?
Do you have a specific budget in mind?
Are you aiming to monetize this idea within a specific timeline?
Any industry you're interested in? (e.g. health, solar, AI)
How to add:
Go to Configure
Scroll to Conversation Starters
Add these questions (or your own based on your GPT’s topic)
Tip: Design these based on what your GPT needs to know before answering. Make them short, relevant, and specific.
▸ Step 7: Test Your GPT
Ensure your GPT behaves correctly:
On the Preview panel (right side), test with sample questions like:
“Suggest me some business idea”Check:
Instruction-following
Tone and format
Accuracy and relevance
Adjust GPT by adding further instructions directly into the Create chat if needed, like:
“Keep answers concise and structured.”
“Always ask about the user’s budget first.”
➜ Example:
I asked
I don’t like how it asks all the questions at once; rather, I want to ask the user one by one.
Lets fix that
Just type my issue in the create section
Problem solved!
Keep fixing until you are satisfied (That's what she….)
Tip: Test multiple scenarios for consistent, quality responses.
▸ Step 8: Customize public facing details (Optional)
Note: All these details are already provided by gpt if you have used create section
Refine GPT’s personality and behavior:
Go back to Configure and set:
Name & Description
Profile Picture (upload or use DALL·E)
Additional behavior instructions (short, clear)
▸ Step 9: Enable or Disable Extra Features (Optional)
Add special capabilities:
Web Browsing (live data)
DALL·E (image generation)
Code Interpreter (data analysis)
Actions (Zapier, Notion integration)
▸ Step 10: Save and Share Your GPT
Finalize and share your GPT:
Click Create (or Update)
Set visibility:
Only you
Anyone with link
Public in GPT store
▸ Step 11: Edit or Delete Anytime
Click GPT name
Select Edit GPT
Update or delete via the menu near Share
That’s it!
⛏ Here’s the Profitable Business Idea Generator GPT
You’ve successfully built a customized GPT that generates smart, personalized business ideas.
Bonus Tip: Regularly updating knowledge files and instructions improves GPT performance over time.
See you in a few days,
Aniket Chhetri
🤔💭 What kind of GPT would you love to build for your work?
Tell us in the comments below.