Are you also staring at the reports in your ad platform with a frown? The click-through rate isn’t bad, but conversions are sparse, and your ad budget feels like a kite with a broken string, drifting off who knows where. Today, with privacy policies getting stricter and third-party cookies being phased out, the traditional “cast a wide net” approach no longer works. It’s like driving in thick fog: dangerous and a waste of money.
In fact, GA4’s first-party data is a powerful searchlight you already hold. This data records in detail who came into the shop, and who picked up a product and put it back down. Using data to drive your campaigns lets you spend every dollar where it counts. Next, let’s turn dry numbers step by step into audience lists that generate returns automatically.
Foundations: pave the road for your data before you set off
For GA4’s intelligent identification to help your advertising, the first step is to link your accounts. Think of GA4 as the “brain” of your marketing strategy and Google Ads as the “hands” that carry it out. If the two aren’t connected, your advertising can only flail around on instinct. Make sure you complete the Google Ads link in the GA4 Admin settings.
💡 Tip: Once the link is complete, remember to turn on Google Signals. This helps the system recognise users across devices, so your data is no longer fragmented.
Next, understand the logic of audience sources. In GA4, an audience is no longer just age and gender, but a collection of behaviours. For example, someone who “stayed on the site for more than three minutes and viewed three product pages” clearly has more commercial value than someone who “clicked an ad by mistake”. Our goal is to turn these specific behaviours into precise lists you can target.
Core application: design your audience model around the marketing funnel
You can’t propose to a stranger the first time you meet, and advertising is the same. Audiences at different stages need different strategies:
- Top of the funnel: build brand awareness
Use GA4’s “interests” and “region” data to find potential new customers. For example, you notice that over the past week, people from Taipei City with a strong interest in “outdoor equipment” visited the site most often. You can then set up an audience to start a conversation with new people who share similar characteristics. - Middle of the funnel: build interest and increase engagement
Target users who have already shown interest in your products, such as visitors who viewed product pages, stayed longer or returned several times. By continuing to show your product’s strengths and differences, you reinforce the brand impression and increase their willingness to take the next step. - Bottom of the funnel: drive conversions and close precisely
For users with clear purchase intent, such as those who added items to the cart but didn’t check out, remarketing ads can remind them and effectively improve the conversion rate.
Example scenario: when a shopper is interrupted by something and abandons a purchase, your ad can gently remind them at the right moment (for example while they’re watching YouTube): “Your item is still waiting for you.” This is the power of a cart recovery strategy.
Advanced optimisation: get the most leverage from every dollar of budget
Once you’ve mastered the basics of targeting, the next goal is the highest possible return on investment.
Set up a “high-value users” label
Not every customer is worth the same. You can use custom dimensions to identify the top 20% of users by lifetime value (LTV). For these “regular customers”, give higher ad weighting and dedicated copy. Or use this group to build lookalike audiences, which is the key to turning a small budget into high sales.
Exclude people who have already converted to protect brand goodwill
💡 Remember: the best ad arrives just when it’s needed; the worst arrives after the fact.
If your customer has already bought that dehumidifier, and then keeps seeing dehumidifier ads for the next week, it’s not only a waste of budget but can also cause irritation. Use GA4 to exclude audiences who “completed a purchase in the past 30 days”, and keep that budget for other potential customers.
Summary and next steps: build your automated audience growth cycle
Data-driven marketing isn’t a one-time setup but a process of continuous optimisation: link accounts ➔ test segments ➔ match precisely ➔ feed data back.
If you run into any of the following when working with GA4 or setting up ad audiences, we’d be happy to talk:
- Stuck linking accounts: Google Ads and GA4 numbers don’t match?
- Unclear audience definitions: not sure which behaviours to set up to identify high-value customers accurately?
- Struggling with data analysis: faced with huge reports, not sure which metric to start optimising?
We’re glad to share what we’ve observed in applying GA4 in practice and help you solve problems with data integration and use.
Questions about using GA4? Get in touch and tell us about your situation, and we’ll give you practical advice and feedback.
