Are you familiar with this: Sending thousands of emails, the only response is the chirping of crickets? I also struggled with flat opening rates, feeling like I was talking to nothing. Until I discovered the "secret weapon" called email segmentation and object grouping. It not only helped me increase my email open rate by more than 200%, but also turned the most "dormant" subscribers into real customers. This is the solution to increase interaction and conversion rate that you are looking for.
How to group audiences so that emails sent are guaranteed to be opened?
To ensure emails are opened, you need to apply email audience grouping criteria based on behavior, demographics and customer journey to send the right message, at the right time.
At Pham Hai, my team and I realized that many small and medium businesses are wasting money by sending the same content for all data. According to the latest statistics, by 2026, email marketing still brings extremely high ROI, averaging 36 - 45 USD for every 1 USD spent. But this number is only for those who know how to send the right message. Blindly sending in bulk not only reduces open rates but also makes you vulnerable to being blacklisted by service providers. To increase email marketing conversion rates, user classification is a step that cannot be overlooked.
According to customer behavior
Grouping by customer behavior helps you "catch" who is about to buy and who is indifferent through shopping history and interaction frequency.
Customer behavior never lies. Closely tracking their purchase history, viewed products, or how often they open emails will provide invaluable "insight". Instead of guessing, you can set up automated email marketing flows that follow their every move on the website or in the mailbox itself.
For example, if a person has just abandoned their cart on your e-commerce site, a reminder email with a small discount code will be extremely effective in bringing them back. On the contrary, for those who have not opened an email for 3 months, you need a separate "warm-up" campaign with a sensational title to rekindle attention. People who frequently click on links (high click-through rate) deserve to receive VIP invitations. This is an important part of marketing. For beginners, learning Email Marketing Beginner's Guide is an important first step in mastering these foundational concepts.
According to demographics
Demographic grouping divides email lists based on age, gender and geographic location to make messages more relevant and "heart-catching".
Don't send emails selling anti-aging cosmetics to male students. It sounds funny, but many people still make mistakes when they don't clean up and filter their email lists. Breaking files down by demographics helps your message feel natural and relevant to your readers' real lives.
You can apply the following basic email audience grouping criteria to optimize your campaigns:
- Tuổi tác và giới tính: Quyết định giọng văn (trẻ trung hay trang trọng) và loại sản phẩm đề xuất. Một thương hiệu thời trang chắc chắn phải tách biệt tệp nam và nữ để gửi bộ sưu tập phù hợp.
- Vị trí địa lý: Cực kỳ hữu ích cho các chương trình khuyến mãi offline hoặc thông báo sự kiện. Chẳng hạn như một ưu đãi freeship áo khoác mùa đông dành riêng cho khách hàng ở Hà Nội, trong khi khách ở TP.HCM lại nhận được ưu đãi áo thun mát mẻ.
- Nghề nghiệp/Thu nhập: Giúp bạn chào bán các phân khúc sản phẩm từ bình dân đến cao cấp mà không làm khách hàng cảm thấy bị xúc phạm hay quá sức mua.
Follow the customer journey
Grouping by customer journey helps you take care of "strangers" into "acquaintances", providing appropriate content for each stage in the sales funnel.
Each person on your list is at a different level in the sales funnel. Customers who have just signed up to receive news (awareness stage) need introductory content and useful knowledge sharing to build trust. Meanwhile, loyal customers (retention stage) expect exclusive offers, points programs or sincere thank you letters.
Sending the wrong message at the wrong time will immediately increase unsubscribe rates. For example, forcing someone who just knows the brand to immediately buy a premium service package is a wrong move. To retain them, you need a clear content roadmap. If you don't know how to build a series of valuable articles to nurture this file, consulting Content Marketing content strategy will help you reshape the funnel in the most methodical way.
"Fatal" mistakes when grouping and the truth about "personalization"
Misunderstanding the concept and confusing grouping with personalization are mistakes that make email marketing campaigns less effective.
Many people complain to me that they have spent a whole week dividing groups but the open rate and ROI are still flat. The cause often lies in our misunderstanding of the nature, or overusing the tools and forgetting the strategic thinking behind them. Why is it necessary to group customers in email marketing if you don't really understand what they want?
What is so "divine" about email segmentation?
Email segmentation is the process of dividing an email list into groups with common characteristics and interests to send targeted messages.
Simply put, instead of sending one "hello to the village" email to everyone, you'll create multiple versions of your message tailored to each subgroup. According to updated data in 2026, campaigns that apply good grouping can increase revenue up to 760% compared to mass email sending.
The benefits of email segmentation go beyond increasing sales. It also helps protect your domain reputation. When users receive relevant content, they will interact more, thereby reducing spam rates and helping you draw a sharper customer portrait. Applying different types of email segmentation also gives you more flexibility in testing new ideas.
Don't confuse Segmentation with Personalization.
Clustering is dividing an audience into files, while email marketing personalization is using data to fine-tune the content within the email for each specific individual.
I see many people equate these two concepts, thinking that just inserting the customer's name into the title will complete the grouping. Actually that is not the case. Clustering (e.g. creating a file of mothers aged 25-30) is the foundation. Personalization is the step of decorating the house, for example, calling them by their first name in an email ("Hello Ms. Lan, how is our baby?").
| Criteria | Segmentation | Personalization |
|---|---|---|
| Mục đích | Split user files | 1-1 interaction with users |
| Dữ liệu dùng | Age group, location, general behavior | Personal name, product just viewed |
| Vai trò | Content strategy direction | Create closeness, promote action |
Good grouping will help personalization become smooth, natural and not "ungainly" in the eyes of the recipient.
I paid a high price for the mistakes I made
Grouping too general, dividing too small and taking time, or not updating the data file are common mistakes that increase unsubscribe rates.
During my career at Pham Hai, I "burned" a lot of budget because of silly mistakes. First, the grouping is too general, dividing it up is almost impossible. For example, just dividing into "men" and "women" for a store that sells technology goods is still very vague. The second is to fall into dividing too much detail (for example: female, in Cau Giay, likes the color red, purchases on Tuesday). It takes time to set up and the file is too small, not worth the effort and operating costs.
The third, and most dangerous, mistake: "falling asleep" on the data. Customer preferences change continuously over time. One person buys baby clothes this year, next year they will need clothes for their toddler. If you don't update groups and streams automatically, your content will become outdated, making customers angry and immediately hit the report spam button.
Practical case study: From zero to effective automated email marketing campaigns for small businesses
Applying the right tools and effective email grouping strategies will help small businesses build automated email marketing flows that bring high ROI.
That's the theory, but putting it into practice is another story. Below is how I implemented an email marketing campaign optimization system from scratch, helping a small e-commerce project revive sales after only 2 months.
Which tool to start with?
Popular email segmentation tools like Mailchimp or GetResponse combined with CRM are the optimal choice to start segmenting customers.
You don't need expensive Enterprise systems from the start. Quick introduction to some popular email segmentation tools that are easy to use for newbies like Mailchimp or GetResponse. In my hands-on experience, Mailchimp has an extremely user-friendly interface that's great for dividing basic files based on demographics. Meanwhile, GetResponse is stronger in behavioral automation and deep integration with CRM systems.
No matter what tool you use, the most important thing is that you must have a quality data file that was collected legally. If you don't have data yet, start right away by Build an email list from scratch for free to have clean raw materials to run the campaign. Never buy floating data, because it will destroy your grouping efforts.
Example of my grouping campaign
By creating 3 automated content streams based on interests, I increased my click-through rate by 161% and maintained sustainable customer engagement.
Năm ngoái, mình nhận xử lý một tệp data 5.000 email bị "nguội" lạnh từ lâu. Instead of immediately sending a massive discount sales email, I decided to play the "slow but steady" strategy. I sent a short survey email, asking about the biggest problem they were facing in skin care. Based on the answers (and tracking people who clicked on each specific link in the email), I divided them into 3 different customer interest groups: Acne Treatment, Anti-Aging, and Moisturizing.
Then, I set up a separate Drip automatic lead nurturing email campaign system for these 3 groups. The content of each stream is deeply customized to the pain of each group. In order for the text to be truly convincing, strike a chord with the psychology and generate orders, I have applied the techniques of Copywriting to write high-converting ads to each title and call-to-action button.
The results were truly unexpected. Open rates skyrocketed from 12% to 35%, and click-through rates (CTR) increased 161% in just 1 month. More importantly, unsubscribe rates dropped to almost zero because everyone felt they were getting truly useful information, tailored specifically to their problems.
Don't try to please everyone with a single email. Start applying email segmentation to your list today, even with just the simplest criteria like "customers who have purchased" and "customers who have not yet purchased". You will be surprised by the change in statistics. Small actions, big effects, believe me!
What grouping criteria are you applying to your campaign? Please share in the comments section below, let's discuss!
Note: The information in this article is for reference only. To get the best advice, please contact us directly for specific advice based on your actual needs.
