How to Make Emails That Customers Open

Email marketing remains one of the most cost-effective ways for small and medium-sized businesses (SMBs) to connect with customers. Yet many business owners, designers, and marketers struggle with the same issue — how do they get people to actually open the emails they send?

1. Understand the Audience First

No subject line, design, or call-to-action can save an email that doesn’t resonate with the right audience. Before writing, define who the message is for. Segment the mailing list based on behaviors, demographics, or purchase history. Doing so ensures the content feels tailored rather than generic. Here are a few practical ways to approach it:

• Behavioral segmentation: Target customers who abandoned their carts with a reminder email featuring product photos.
• Demographic segmentation: Send location-specific promotions, like a weather-appropriate clothing sale.
• Life cycle segmentation: Offer discounts to new subscribers, while loyal customers may prefer early access to new products.

2. Compose Subject Lines That Spark Curiosity

The subject line is the gatekeeper. In fact, about 33% of recipients rely only on the subject line when choosing whether to open an email. Effective subject lines are short, specific, and relevant. Below are some tips to consider:

• Keep subject lines under 50 characters so they don’t get cut off on mobile screens.
• Use action-oriented language, like “Unlock,” “Claim,” or “Discover.”
• Avoid spam triggers such as excessive exclamation marks, ALL CAPS, or phrases like “Buy now.”
• Test variations with A/B testing to see what works best.
• Pair subject lines with preheader text — the two should work together, not repeat each other. A subject line teases, while the preheader adds context.
• Leverage urgency carefully, with phrases like “Ending soon” or “Last chance,” but avoid overusing them to prevent fatigue.
• Experiment with tone and style. Conversational subject lines like “Forgot something in your cart?” often outperform corporate ones such as “Reminder: Complete your purchase”.
• Use numbers or lists when appropriate. Examples like “3 quick fixes for your workspace” tend to catch attention because they promise concise, structured value.

3. Balance Text and Images

Emails that rely too heavily on visuals can backfire. Spam filters often flag image-only emails as suspicious because scammers use them to disguise harmful content. A safe rule of thumb is to keep a 60:40 text-to-image ratio, ensuring enough copy for filters to scan while leaving room for visuals that make the message appealing. 

To put this into practice, use real text instead of embedding all words into graphics, add descriptive alt text to images, and ensure the copy carries the main message. This way, the design looks polished while still staying inbox-friendly.

4. Incorporate Personalization Beyond First Names

Including a customer’s first name helps, but personalization has to go deeper. Dynamic content allows businesses to tailor subject lines, images, or product recommendations based on customer history.

Amazon is a leader in this area — its product suggestion emails are highly personalized, leveraging browsing history and prior purchases. Smaller businesses can use customer relationship management tools to achieve similar results on a smaller scale.

Notably, emails tailored to the recipient’s interests perform dramatically better — driving six times higher transaction rates than non-personalized campaigns. Even modest personalization can make a measurable difference.

5. Remember That Timing Is Everything

Even the best email will be ignored if sent at the wrong time. The ideal moment varies by audience, industry, and even seasonality — which means guessing rarely works. Use analytics to determine when a specific audience is most active, and refine based on actual performance rather than assumptions.

Many email service providers now offer send-time optimization, automatically delivering emails when each subscriber is most likely to open. This takes the guesswork out of scheduling and ensures the message appears at the top of the inbox at the right time. Here are some additional tips to try:

• Test different days of the week: For some businesses, midweek mornings perform best — for others, weekends or evenings drive more engagement.
• Consider customer habits: A restaurant might see stronger open rates in the late afternoon before dinner, while a B2B company may get more traction during working hours.
• Pay attention to time zones: If the target audience is spread across regions, schedule emails to arrive at a consistent local time rather than blasting everyone at once.
• Review seasonal trends: Engagement patterns often shift around holidays or major events, so adjust accordingly.

6. Optimize for Mobile First

Most people check their inbox on their phones first, meaning emails must be easy to read and navigate on smaller screens. A clunky or hard-to-read message is unlikely to get a second chance. The best way to avoid this is by keeping the layout simple with a single-column design, making subject lines and preheaders short enough to scan quickly, and ensuring buttons are large enough to tap without zooming in. 

Limit heavy images that can slow load times, and always preview the email on multiple devices before sending. Optimizing for mobile is more than just about design — it’s about respecting how and where audiences actually engage with content.

7. Deliver Value Every Time

Customers should feel that opening a brand’s emails is worth their time. If the content consistently feels valuable — discounts, insights, or relevant updates — they’ll open more often. If it feels irrelevant, they’ll unsubscribe.  Consider these approaches:

• Exclusive offers: Early access to sales or member-only discounts.
• Educational content: Tutorials, how-to guides, or case studies. For example, a design software company might share tips for creating high-quality graphics.
• Entertaining elements: Lighthearted polls or interactive quizzes to boost engagement.

8. Use Preheaders Wisely

The preheader text is the snippet that appears after the subject line in most inboxes. It often acts as the second pitch to convince a customer to open. Instead of leaving it as default text like “View in browser,” craft preheaders that complement the subject line. For instance:

• Subject line: “Ready for sweater weather?”
• Preheader: “New arrivals that keep you warm without breaking the bank.”

9. Test, Measure, Refine

Email marketing should never be treated as a set-and-forget effort. The most successful campaigns are built on continual testing and learning. Track key metrics such as open rates, click-through rates, and conversions to see how the audience responds, then adjust the strategy accordingly. 

A/B testing is especially valuable for comparing subject lines, layouts, or send times to determine what resonates best. Heatmaps can highlight where readers are clicking inside emails, while short surveys provide direct feedback on what subscribers want more of. Each insight — no matter how small — adds up over time, helping fine-tune the approach and steadily improve results.

10. Respect Frequency and Privacy

Too many emails can lead to fatigue, while too few can make customers forget a brand exists. Striking the right balance is key — overwhelm subscribers and they may unsubscribe, but disappear for weeks and they may disengage or lose interest. Frequency should align with the type of content sent out and the expectations set at signup. 

For example, a daily deals site might email more often without pushback, while a consulting firm may see better results with a weekly or monthly cadence. Giving subscribers options to choose their preferred frequency can also reduce churn and build trust, since it puts control back in their hands.

Moreover, respecting privacy is equally important. Regulations like the General Data Protection Regulation in Europe and the CAN-SPAM Act in the United States require clear opt-in processes and easy unsubscribe options. Beyond compliance, honoring customer preferences builds trust.

11. Learn From Case Studies

Some of the most effective email strategies can be seen in real-world examples. Airbnb uses personalized recommendations and a clean design to drive bookings, often highlighting properties based on a user’s recent searches to reinforce relevance. 

Dropbox takes a different approach with re-engagement emails that rely on simple visuals and concise calls-to-action, making it easy to win back inactive users. BuzzFeed focuses on tone and structure, keeping subject lines conversational and content short and snackable, which leads to consistently high reader engagement. 

SMBs can borrow from these tactics on a smaller scale by emphasizing relevance, simplicity, and customer value in every message.

Turning the Inbox Into Opportunity

Getting customers to open emails is not about gimmicks — it’s about delivering consistent value that feels relevant, timely, and respectful of their time. By focusing on audience understanding, compelling subject lines, thoughtful personalization, and continuous testing, SMB owners and marketers can transform email from a background noise channel into a reliable driver of engagement and revenue.