The subject line in an email is the first impression we leave on our readers, and as they say, there is no second chance to make a good first impression. More than 300 billion emails are sent every day, so standing out in the inbox is a challenge, but not an impossible one. And part of this we do by writing good issues in emails.
How many times have we decided to open an email just because the subject line caught our attention? Perhaps it generated curiosity, promised to solve a problem, or simply connected with our emotions. Conversely, how many emails have we ignored because their subject line seemed generic, irrelevant, or even suspicious? This is the power (or risk) of email subject lines.
In this article, we teach you how to write eye-catching subject lines, grab our readers’ attention, and test different approaches to identify what works best.
How to write attention-grabbing email subject lines
The first step to writing subjects in effective emails is to understand what makes them stand out. A good subject line captures attention, conveys the value of the content, and motivates the reader to open the email. Here’s how to do it.
1. Be clear and specific
Clarity is paramount when it comes to subject lines. Readers should know exactly what to expect when they open the email. Vague or confusing subject lines tend to be ignored, while clear and specific ones generate confidence and curiosity.
Example:
- Generic subject line: “What’s new this month”.
- Clear subject: “5 B2B marketing trends you should know about today”.
Why does it work? A clear subject line shows that we respect our readers’ time by quickly communicating the value of the content. According to a Campaign Monitor study, specific subject lines are 26% more likely to be opened.
2. Use numbers and lists
Numbers and lists capture attention because they are easy to process and promise structured, digestible content. This approach is especially useful in educational or informational mailings.
Example:
- “3 ways to optimize your email marketing campaigns”.
- “10 essential tools for B2B marketing”.
Why does it work? Numbers create expectations about the content and generate curiosity. They also convey a sense of concreteness and organization.
3. Appeal to emotions
Emotions are a powerful driver of action. An issue that touches on emotion, whether curiosity, urgency, surprise, or empathy, is more likely to generate an opening.
Example:
- “Are you making this mistake in your email campaigns?”.
- “Discover the secret that will increase your conversions by 50%.”
Why does it work? Emotions spark interest and connect with readers on a more personal level, making them more likely to interact with the email.
How to grab attention with subject lines in emails.
Standing out in the inbox is an art that combines creativity, psychology, and knowledge of our audience. Here we explore specific strategies to make our business shine.
1. Personalization
Personalization goes beyond including the recipient’s name. It is about adapting the subject line to the context, interests, and needs of each reader.
Example:
- “Juan, here are the strategies your business needs”.
- “Exclusive ideas for technology companies”.
Why does it work? According to a Statista study, emails with personalized subject lines are 50% more likely to be opened. Readers feel that the content was designed specifically for them.
2. Create a sense of urgency
Urgency is a tool to motivate immediate action. Words like “today,” “last chance,” or “now” drive readers to open the mailer before it’s too late.
Example:
- “Last day to access this exclusive discount”.
- “Registration for our webinar ends today”.
Why does it work? Urgency activates FOMO (fear of missing out or fear of missing out), a psychological response that generates a sense of priority.
3. Arouse curiosity
Subjects that generate curiosity without revealing too much can be irresistible to readers. The key is to create a little mystery that motivates them to find out more.
Example:
- “The secret behind the most successful campaigns”.
- “What do leading companies do that you don’t?”.
Why does it work? Curiosity is intrinsic to human beings. By generating questions in the reader’s mind, we increase the likelihood that they will open the mail to find answers.
How to test different subject lines in e-mails
Writing a good subject line is only the first step. To make sure it is effective, we must continually test and adjust it. This is the importance of A/B testing.
1. What is an A/B test on email subject lines?
An A/B test consists of sending two different versions of a subject line to equal segments of our audience. Then, we analyze which one generates better results (such as open rate) and use that version for the rest of the list.
Example:
- Subject A: “5 strategies to improve your emails”.
- Subject B: “Do your emails need a change? Here are 5 ideas.”
Why does it work? This data-driven approach eliminates guesswork and allows us to identify what resonates most with our audience.
2. Elements to test
When running A/B tests, it is useful to experiment with different elements of the subject line to understand what works best:
- Tone: Formal vs. casual.
- Length: Brief vs. detailed.
- Style: Declarative vs. question.
Example:
- Formal tone: “Essential updates for your business”.
- Casual tone: “Look what we have in store for you!
3. Analyze the results
When evaluating the results of an A/B test, pay attention to metrics such as:
- Open rate: Which subject line generated the most initial interest?
- Click-through rate: Which issue led to most interaction with the content?
- Cancellation rate: Did any topic generate disinterest or rejection?
Example: An A/B test reveals that subject lines with questions generate 15% more opens than declarative ones. The brand decides to use questions in future emails to better capture attention.
Psychology and creativity in email subject lines
The best subject lines also connect, they manage to capture attention because they leverage psychological principles that resonate with human emotions and needs. In addition, a good use of creativity, such as storytelling or a tone that reflects the brand voice, can transform an ordinary mailing into a memorable experience. Let’s look at how to integrate psychology and creativity into email copywriting.
1. How to apply psychological principles to issues
Psychology offers us powerful tools to create issues that engage. By understanding how people think and react, we can design messages that motivate them to act.
- a) Curiosity: is a natural engine that drives people to seek answers. The subjects that generate questions or present incomplete mysteries are irresistible to the brain.
- Example:
- “What are the leading companies doing that you’re not?”.
- “Discover the trick that’s doubling conversions.”
- Why it works: according to studies by the University of California, curiosity activates the region of the brain related to reward, causing people to seek more information.
- b) Urgency: generates an immediate response by making the reader feel that something valuable is at risk of being lost.
- Example:
- “⏳ Last day to take advantage of this discount”.
- “Only 2 spots left for our webinar”.
- Why it works: Urgency triggers FOMO and motivates people to act so as not to be left behind.
- c) Sense of belonging: people want to feel part of something, whether it is a community, an exclusive group, or a trend.
- Example:
- “Join the leaders who are transforming marketing.”
- “For our VIP subscribers only: early access.”
- Why it works: according to Tajfel’s self-identity theory, people tend to respond positively to messages that reinforce their sense of belonging.
2. Storytelling on an issue
storytelling is not reserved for long articles or advertisements. It can also be applied in subject lines, creating micro-stories that capture attention and arouse emotions from the first glance.
How to tell a micro-story:
- Present a conflict or challenge: introduce a problem that your audience can relate to.
- Example: “Why do most email campaigns fail?”.
- Suggests a solution: indicates that the email contains the answer or the outcome.
- Example: “Find out how we prevented this campaign from failing”.
- Make it personal: use a tone that makes the reader feel included in the story.
- Example: “When we faced this problem, we learned a lesson.”
Benefits of storytelling in business:
- Engages emotionally: stories activate more areas of the brain than simple facts or statements, which makes the message memorable.
- Generates curiosity: the reader will want to know how the story ends.
- Connect on a personal level: by telling real or situational stories, you establish empathy with your audience.
Example:
- Before: “Discover how to improve your results”.
- Then: “How we doubled our open rates in 30 days”.
3. The impact of brand tone and voice.
The tone and voice you use in your subject should reflect your company’s personality and resonate with your audience. Adapting the style improves the consistency of your communication and also builds a deeper connection with your readers.
- a) What is a brand voice? It is the unique way your company communicates. It can be professional, friendly, approachable, or inspiring, depending on your identity and your audience.
- b) Tone according to the intention:
- Promotional: focused on generating excitement or urgency.
- Example: “Don’t miss out on this unique discount!”
- Educational: clear and direct.
- Example: “Practical guide to optimizing your campaigns”.
- Inspirational: thoughtful and motivational.
- Example: “Your next big step in marketing starts here”.
- c) How to stay consistent:
- Know your audience: understand what tone connects best with them.
- Define your values: use words and phrases that reflect your brand’s mission and vision.
- Be consistent: make sure your tone is consistent across all touchpoints, from email to social media.
Example: a technology brand adopts an innovative and optimistic tone:
- Before: “New features available.”
- Then, “🚀 Take your productivity to the next level with these new tools.”
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Choosing the right terms can influence whether an email is opened or ignored.
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Advanced strategies for email subject lines
Mastering the art of writing effective email subject lines implies creativity and clarity, but also the ability to take advantage of advanced tools and techniques that optimize interaction with our recipients. Let’s see what strategies we are referring to:
1. The power of keywords in subject lines
Keywords are not only relevant for SEO; they also play a role in email subject lines. Choosing the right terms can influence whether an email is opened or ignored. These words act as emotional or rational triggers that capture attention and convey value immediately.
How to choose effective keywords:
- Know your audience: identify which words or phrases resonate with your target audience. For example, terms such as “exclusive”, “free” or “savings” tend to capture attention.
- Align with your objectives: use words that are directly related to the action you expect the recipient to take, such as “buy”, “book”, “download” or “sign up”.
- Use action verbs: words like “discover”, “take advantage” or “learn” generate a sense of urgency or interest.
Example:
- Before: “June newsletter”.
- After: “Discover the 5 trends that are revolutionizing marketing”.
Benefits:
- Immediate relevance: keywords help the reader quickly understand what the email is about.
- Improved open rates: According to Campaign Monitor, subject lines with specific keywords are 20% more likely to be opened.
Tip: test different keywords to identify which ones generate better results in your audience segments.
2. Use of emojis in the subject lines
Emojis have become a visual resource when used correctly and can make a subject line stand out in the inbox. However, their use must be strategic to avoid saturating or distracting the reader.
Pros of using emojis:
- They attract attention: emojis stand out visually in a mailing list, especially on mobile devices.
- They convey emotions: an emoji can reinforce the tone of the message, whether it is casual, urgent, or exciting.
- Small space: they allow compact communication of complex ideas.
Cons of using emojis:
- Limited relevance: if the emoji is unrelated to the content, it may confuse the reader.
- Risk of saturation: excessive use may appear unprofessional or tire the recipient.
- Compatibility: some emojis may not display correctly in certain email clients.
When and how to use them:
- In casual promotions: for e-commerce, events, or holiday campaigns. Example: “🎉 Last chance: 30% off this weekend”.
- To highlight urgency: Example: “⏳ Only 2 days left to register”.
- On specific audiences: Emojis work best with younger audiences or in creative industries.
Example:
- Before: “Special offer available for a limited time”.
- Then: “🔥 Special offer! Only available for 48 hours.”
Tip: use emojis sparingly and make sure they reinforce the message instead of distracting. Always test to verify their effectiveness in different segments.
Common mistakes and how to avoid them in email subject lines
Although writing effective subject lines in emails, many common mistakes can reduce their impact. So, below we’ll explore how to identify and avoid these mistakes, as well as recognize when it’s time to adjust your strategy.
1. Common mistakes when writing email subject lines
Subject lines should be precise, attractive, and relevant, but certain mistakes in their wording can cause the opposite effect. Here are the most common ones and how to avoid them:
(a) Use of “spammy” words.
Words such as “free”, “unmissable offer” or “get rich quick” are perceived as untrustworthy by both readers and mail filters. This type of language is often associated with unwanted emails and reduces the likelihood of opening.
- Example of an error: “Earn easy money! Offer for today only”.
- Alternative: “3 strategies to increase your income quickly”.
- b) Vague or confusing subject lines
A generic subject line that does not communicate the value of the mailing leaves readers disinterested. Lack of specificity can cause the message to be ignored.
- Example error: “Monthly update”.
- Alternative: “Find out what is trending this month”.
- c) Exaggerated or misleading promises
Issues that promise something too good to be true generate mistrust and, if they do not deliver what was promised, damage the relationship with subscribers.
- Example of an error: “Lose 10 kg in one week without effort”.
- Alternative: “Tips backed by experts to improve your health”.
- d) Excessive use of capitalization or punctuation.
Subjects with too many capital letters or exclamations can appear aggressive or unprofessional and are often detected as spam.
- Example error: “UNIQUE OFFER!!! DON’T LOSE IT!!!”.
- Alternative: “Exclusive offer for you: discover more here”.
2. How to prevent your subjects from being marked as spam
Even a good subject line can end up in the spam folder if certain technical and content factors are not taken care of. Here is how to prevent this problem:
(a) Comply with mailing regulations: laws such as the CAN-SPAM Act or the RGPD require transparency in communications. To avoid problems:
- Always include an unsubscribe link.
- Use a valid and recognizable sender address.
- Make sure that the content of the email is related to the subject line.
- b) Avoid practices detected by spam filters, such as:
- Spammy words: avoid terms such as “100% free”, “click here”, and “instantly approved”.
- Excessive symbols: using too many emojis or punctuation marks can trigger filters.
- Use of shortened URLs: they may look suspicious, especially if they are not related to the sender.
- c) Take care of your reputation as a sender: mail providers monitor the reputation of your domain and IP address, so keep it high:
- Send mailings only to lists of contacts who have given their consent.
- Regularly clean your lists to remove inactive or bounced addresses.
- Be sure to correctly configure SPF, DKIM, and DMARC in your domain.
- d) Maintain consistency between subject and content: Spam filters detect discrepancies between the subject and the content of the email. Make sure both are aligned to avoid deliverability problems.
3. Signs that your business strategy needs tweaking
Even the best strategies require adjustments over time. Here are some key indicators that your business is not performing as it should and needs an overhaul:
- a) Declining open rate: If you notice a steady drop in opens, it could be a sign that your subject lines are not resonating with your audience. Possible causes include:
- Lack of relevance or personalization.
- Frequency of mailings too high or too low.
- Topics that no longer interest subscribers.
- b) Increase in unsubscribes or spam complaints: An increase in unsubscribes or spam complaints indicates that your emails are saturating or irritating recipients. This could be due to:
- Sensationalistic or misleading subject.
- Lack of connection between the subject and the content.
- The frequency of mailings is not aligned with the reader’s expectations.
- c) Low content engagement: If click-through rates and conversions are low, it could mean that the subject line attracts opens, but does not meet reader expectations. This may be a sign that issues need to be more specific and transparent.
- d) Direct feedback from subscribers: negative comments, whether through surveys or direct interactions, are a valuable source of information on how to improve your issues.
How to address these issues:
- Survey subscribers: ask what type of content and frequency they prefer.
- Analyze segmented metrics: identify if certain segments of your audience are responding better than others.
- Try different approaches: perform A/B tests to experiment with tone, length, and focus.
Conclusions
As we have seen, knowing how to write good subject lines in emails is not something we can leave to chance. The subject line is that little hook that has the power to capture the attention of our readers… or lose it completely. It’s the first impression, and as you know, that counts for a lot.
So let’s do a recap. First, keep your subject clear and specific. Be honest with what you offer and make sure the content meets the expectations you generated. Also, don’t underestimate the power of keywords and small details, such as a well-placed emoji or a question that arouses curiosity.
Of course, it’s not all about creativity. You have to test, measure, and adjust. A/B tests are your best allies to understand what works and what doesn’t. Are your open rates dropping? Maybe you need to refresh your approach. Are there spam complaints? Review your technical practices and content.
Not all mistakes are fatal if we are attentive to correct them. The most important lesson? Connect with your audience. If you know what they need and how to talk to them, you’re halfway there.
So, ready to try something new in your next emails? Start with the subject line: a powerful line can open many doors.
