How to write great subject lines for your marketing emails

The difference between an email that gets opened and one that doesn’t often comes down to just a few carefully chosen words. Whether you’re crafting cold email subject lines to reach new clients, following up on a sales pitch, or building your network, mastering the art of subject lines is crucial.

Recent research analyzing billions of emails has uncovered surprising truths about what actually works, and it’s not what most marketers think! Knowing exactly what to include in email subject lines for different situations—whether it’s a cold outreach, a follow-up, or a networking email—can dramatically increase your success rates.

Should you include someone’s name in your subject line? What elements drive the highest open rates? From reaching out to new contacts to nurturing existing relationships, we’ll explore data-backed strategies that will transform how your emails perform.

What research tells us about email open habits

So, what actually works when it comes to email subject lines? Do you put your name in email subject lines? How do you know what to include in email subject lines?

As the old saying goes, “Without data, you’re just another person with an opinion.” 

Let’s dive into some fascinating data. A recent study by the email and SMS marketing tool Attentive analyzed over 7.5 billion email subject lines and uncovered some surprising insights about what makes people open.

The most interesting finding? There’s a crucial difference in what works for triggered emails (like welcome messages or abandoned cart reminders) versus campaign emails (like sales announcements or product launches.) An email subject line for sales will differ from one for an educational email, for example. Let’s break down the key learnings:

For “triggered” or transaction emails:

• Personalization is your friend. Including a customer’s name or the product they viewed actually boosts open rates.
• Medium-length subject lines (25–35 characters) perform best.
• Using “you” or “your” helps drive engagement.
• Skip the emojis as they actually hurt performance for these types of emails.

For campaign emails:

• Keep it clean and skip personalization. It can feel forced and wastes precious character space.
• Shorter is better. Aim for less than 25 characters.
• Avoid “you” and “your.” These emails go to broader audiences, where personal touches can feel inauthentic.
• Again, leave out the emojis, as they take up space without adding value.

The key takeaway? The era of trying to grab attention with gimmicky subject lines is over. Great email subject lines are tailored and targeted. Today’s email recipients are sophisticated and respond best to subject lines that clearly communicate value while respecting their intelligence.

According to Attentive’s research with Forrester, brands that nail their email subject line strategy (along with other email best practices) can achieve $2.2M in profits from their email programs by year three. It’s a huge return on investment for simply sharpening your subjects.

The psychology of effective subject lines

Think back to when you last checked your email inbox. Chances are, you made split-second decisions about which messages to open and which to ignore. But what drives those quick choices?

The science of email opens

Here’s what research tells us: we don’t consciously analyze every subject line. Instead, our brains rapidly filter for two key factors:

• Trust: is this from someone or something we care about?
• Value: does this matter to us right now?

The numbers back this up. AWeber’s 2024 research shows that 99% of email subscribers check their email every day, with 58% making it their first digital task each morning.

When they do, they’re making lightning-fast decisions about what to open. That same study found that 42% of subscribers open based primarily on the sender’s name, while 47% make their decision based on the subject line alone.

What makes us click

People open emails that connect with their “inner landscape.” This includes their current needs, challenges, and aspirations. Think about your own behavior. You probably open every email from your boss without thinking twice. But a marketing email? It needs to promise clear value in seconds.

The data supports this behavioral insight. According to Litmus’s latest analysis, email marketing generates an average return of $36 for every $1 spent, making it one of the most effective channels for reaching customers who actually want to hear from you. This high ROI comes from understanding and addressing specific audience needs.

Recent research from MailerLite’s 2024 industry study reinforces these findings. Their analysis reveals how ROI varies across different sectors:

• Marketing and advertising agencies achieve returns of 42:1
• Retail and e-commerce businesses see even higher results at 45:1
• Entertainment and media maintain a robust 32:1

These numbers far outperform other marketing channels—with social media averaging 250% ROI and Google Ads returning $8 for every dollar spent, according to the same study.

The takeaway is clear: successful subject lines resonate with what matters to your readers right now. When your subject line speaks directly to what keeps your readers up at night (or gets them excited in the morning), you’ve got their attention. And in today’s crowded inboxes, that attention is golden.

6 strategies for subject line success

Want to transform your email open rates? Let’s explore six proven strategies that top marketers use to craft subject lines that get results.

1. Build the right foundation

Setting clear expectations from the start makes all the difference. When someone joins your email list, tell them exactly what they’ll receive. A monthly newsletter? Daily tips? Special offers? Being upfront helps attract subscribers who actually want your content.

But here’s the key: stick to what you promised. If you offered exclusive design tutorials, don’t suddenly switch to pure promotional content. Consistency builds trust, and trust drives opens.

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2. Make it matter

The best subject line in the world won’t work if your content isn’t relevant. Your subscribers have specific needs, challenges, and goals. Your job? Show them you understand.

Study your audience’s behavior. What content gets the most engagement? Which subject lines drive the highest open rates? Use these insights to craft subject lines that speak directly to what your subscribers care about most.

3. Use personalization wisely

Modern email platforms offer powerful personalization options, but use them strategically. Including someone’s name can boost open rates for welcome emails and important updates. But for general campaigns? Less is often more.

When deciding if you should put your name in email subject lines, consider the relationship. For triggered emails like order confirmations, it can boost recognition. For cold email subject lines, it’s often better to focus on value proposition.

Instead of basic name insertion, try personalizing based on behavior or preferences. Reference past purchases, browsing history, or location when relevant. It’s about being helpful, not creepy.

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4. Create connection

Emotional resonance matters. While you don’t need every subject line to be a masterpiece, aim to spark interest or curiosity. Ask engaging questions. Share surprising statistics. Tell micro-stories that make subscribers want to learn more.

Great email subject lines for sales often take an emotional approach. They create urgency, curiosity, or highlight specific benefits. Your follow-up email subject lines should reference previous conversations while adding new value.

Just keep it authentic. Your subscribers can spot forced enthusiasm from a mile away. Focus on genuine value and natural engagement.

5. Nail the technical details

Mobile optimization isn’t optional anymore—it’s essential. Most email opens happen on phones, so front-load your subject lines with the most important information. Those first 25 to 30 characters need to work hard.

Watch your formatting too. Special characters can add personality, but too many symbols or emojis can trigger spam filters. Keep it clean and professional.

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6. Measure, monitor, adapt

Success leaves clues. Track your open rates across different subject line styles, lengths, and sending times. What works for one audience might flop with another, so let the data guide you.

Set up regular A/B tests to compare different approaches. Then use those insights to continuously refine your strategy. The best email marketers are always learning and adapting.

How to generate more ideas for great email subjects

There’s no doubt that for email marketers, writing good subject lines matters. But even for the most creative of us, ideas don’t always come easily. This is especially the case as there’s so much to consider while composing subject lines.

Different contexts require different approaches. The subject line of a networking email might highlight mutual connections, while an email subject line for reaching out to new prospects should clearly state your value proposition.

Start your swipe file

Think of your swipe file as your highlight reel of winning subject lines. When an email makes you stop scrolling and click, save that subject line.

These are your real-world examples of what works. Some will grab you because they’re personally relevant. Others might showcase clever wordplay or perfect timing. All become inspiration for your own campaigns.

Grow your idea garden

Your idea garden is where spontaneous inspiration takes root. Maybe a subject line idea hits while you’re in line for coffee. Or you brainstorm five campaign concepts during your morning commute.

Don’t let these ideas slip away. Capture them all in your idea garden. Like any garden, some ideas will bloom right away while others need time to develop into full campaigns.

Get an assist from AI (and test the results)

AI tools like ChatGPT can supercharge your subject-line brainstorming sessions in 2025. Feed them specific details about your audience and campaign goals, then use their suggestions as creative starting points to develop your own unique angles. Remember to mix in your brand voice and understanding of your customers.

But don’t skip the testing phase. AI-generated lines still need real-world validation. Run A/B tests to see how they perform against your traditional subjects. Track metrics like open rates and click-throughs across different segments. The best results often come from combining AI’s pattern-recognition capabilities with your marketing instincts.

Now you’re ready to send emails that get opened

Remember that great email subject lines aren’t universal. They’re perfectly matched to both audience and purpose. A subject line that works brilliantly for nurturing existing customers might fail completely when used for cold outreach.

Ready to put these strategies into action? Start by exploring Envato’s collection of professional email templates. From sleek newsletters to engaging promotional campaigns, you’ll find everything you need. Plus, with customizable templates, you can maintain brand consistency while saving valuable time.

Remember: the perfect subject line opens the door, but it’s your email content that seals the deal. Keep experimenting, testing, and refining your approach. Your future open rates will thank you!