How to create a Gemini Gem for your marketing, step by step

Every time you open Gemini you explain who you are, who you sell to and how you write. A Gem saves you that step: it stores your instructions and applies them in every conversation. With over 1 billion people using the Gemini app each month, according to Alphabet, it's worth learning to use it well. Explain it once, use it always.

What is a Gem and why create one in Gemini for your marketing?

A Gem is a version of Gemini with saved instructions for a specific task. You create it once and then pick it from the side panel, like opening a folder. Google opened it to all users, at no cost, in March 2025.

The upside is that you stop starting from scratch in every chat. With the same instructions, the answers come out closer to the way you work, so think about the tasks you repeat every week.

Note one difference: a Gem answers and helps you, but it doesn't act on its own in other tools. That's what an AI agent does, as we explain in how AI agents are changing marketing.

A Gem is an assistant that remembers your instructions, not an employee.

Which marketing Gems can you create today?

These three work for almost any small business:

• LinkedIn writer with your voice: you give it 3 of your posts as examples and it turns an idea into a draft.
• Ad reviewer: it checks that each text has a clear benefit, proof and a call to action. It also flags any promise you can't keep.
• Review replies: it writes a friendly draft for each Google review, in your brand's tone, for you to check.

At Garcai we think the best first Gem is for the task you find most boring. That's where you'll notice the time saved soonest. For more ideas, see our guide to prompts for ad copy (ready-made instructions for asking AI to write ads).

What shouldn't you put in a Gem's instructions?

Google reminds you to review what Gemini generates before publishing it or relying on it. And whatever you upload stays in your Google account.

• Customers' personal data, such as names, phone numbers or emails.
• Passwords, access keys or bank details.
• Confidential company information you wouldn't share with a supplier.

A Gem works with what you give it: give it your style guide and public examples, not your customer list. If you use a work account, your company's rules also apply.

The Garcai method: create your first marketing Gem in 10 minutes

Follow the steps in Google's help, on a computer:

1. Go to gemini.google.com, open the side panel and click ‘Gems’, then ‘New Gem’.
2. Write a clear name, for example ‘LinkedIn writer’.
3. Write the instructions using the template below. If you get stuck, use the button that asks Gemini to rewrite them.
4. Optional: under ‘Knowledge’, click ‘Add files’ and upload your style guide or 3 sample texts of yours.
5. Test it in the preview on the right, adjust what you don't like and click ‘Save’.

A 4-part instruction template (change what's in square brackets):

• Who you are: ‘You're the marketing assistant for [business], a [type of company] in [city] that sells [product] to [type of customer]’.
• Task: ‘Your job is [task], for example, turning an idea into a LinkedIn post’.
• Format: ‘Reply with [format], for example, a headline, 3 short paragraphs and a closing question’.
• Tone: ‘Write in a [friendly] tone, without jargon. If you're missing information, ask me instead of making it up’.

You can do it yourself: all 5 steps with your personal Google account.

Ask your tech team if you use a work account and want to add files from Drive. Message ready to copy: ‘Can you enable Gemini and its Google Drive connection on my work account? I want to create a Gem with our style guide’.

Common mistakes when creating a Gemini Gem

• Writing one-line instructions, like ‘help me with marketing’: the Gem knows nothing about you.
• Not giving it examples of how you write.
• Creating one Gem for everything: it works better with one per task.
• Publishing what it writes without checking it.
• Uploading customer data or confidential information.

A Gem won't make you a better professional, but it takes repeated work off your plate. Explain it once, use it always. And if you also want to use AI to rank your site, read our guide to ChatGPT for SEO.