10 Essential Email Subject Line Lessons (Straight From My Inbox)

15 Proven Email Subject Line Lessons to Boost Your Open Rates in 2023

What‘s the first thing you look at when deciding whether to open an email? That‘s right, the subject line. In many ways, the subject line can make or break the success of your entire email campaign. It‘s your one shot to grab the reader‘s attention and convince them your message is worth reading.

But with the average office worker receiving over 120 emails per day, standing out in a crowded inbox is harder than ever. On top of that, nearly 50% of all emails are now opened on mobile devices, meaning your subject lines need to be concise, compelling, and optimized for smaller screens.

As we head into 2023, mastering the art of the email subject line is more critical than ever for engaging your audience and driving results from your email marketing efforts. In this post, we‘ll share 15 subject line approaches that have been proven to boost open rates, along with real-world examples you can learn from. We‘ll also discuss emerging trends and best practices to help you craft subject lines that cut through the noise and connect with your readers.

  1. Spark curiosity by asking a question
    Asking a question in your subject line is a great way to engage readers and prompt them to reflect on their own experiences. Questions create an innate human desire to uncover the answer. Try subject lines like:
    • "Quiz: How much do you really know about [topic]?"
    • "What‘s your biggest challenge with [pain point]?"
    • "Pop quiz: Can you guess the top 3 [blanks]?"

Example: Moz – "What do the top 1% of pages have in common?"

  1. Create a fear of missing out (FOMO)
    FOMO is a powerful psychological driver. Nobody wants to miss out on an amazing deal or opportunity. Use your subject lines to highlight scarcity, urgency, and exclusivity:
    • "[24 Hours Only] 50% off all items"
    • "Tonight only: Exclusive invite for [Name]"
    • "Only 3 spots left! Reserve your seat now"

Example: Oyster – "Uh-oh, your credit card is about to expire"

  1. Keep it short and punchy
    With nearly half of all emails opened on mobile devices, brevity is key for subject lines. Aim for 30 characters or less so your full message displays on smaller screens. Get creative with wordplay and leading statements:
    • "Stop wasting $ on [blank]"
    • "The secret to [benefit]?"
    • "Yes, it‘s really free…"

Example: Eater Boston – "Where to Drink Beer Right Now"

  1. Get personal(ized)
    Personalized subject lines are 26% more likely to be opened. Use merge tags to dynamically insert each recipient‘s name, location, or other personal details you‘ve collected. Just be mindful of data privacy regulations like GDPR.
    • "Hey [Name], check out these offers in [City]"
    • "Based on your order history, you might like…"
    • "Wow, [Name]! $50 off, just for you"

Example: Sephora – "Happy Birthday Mary – Surprise Inside!"

  1. Make a big promise or bold claim
    Grabbing attention often requires a bit of shock value. Don‘t be afraid to make a big, bold, benefit-driven promise (as long as you can back it up in the email body):
    • "The 10-minute workout that burns 500 calories"
    • "98.7% of customers doubled their revenue with [blank]"
    • "Learn to [skill] in 30 days, guaranteed"

Example: Hustle – "How I built a $10k/mo side project"

  1. Use numbers, lists, and stats
    There‘s a reason listicles are so popular – our brains love numbers and lists. They create an enticing promise of quick, easily digestible information. Use numbered lists and stats to add credibility and intrigue:
    • "Top 10 tools for [audience]"
    • "5 data-backed ways to [benefit]"
    • "47 marketers share their top tips"

Example: BuzzFeed – "21 Things You‘ll Understand If You‘re a 90s Kid"

  1. Speak the language of your audience
    Aim to reflect the communication style of your target persona. Consider their age, role, interests, goals, and challenges. Don‘t be afraid to get playful with abbreviations, slang, pop culture references, or emojis as appropriate.
    • "Hey squad, who‘s coming to [event]? 🙋‍♀️"
    • "3 ways you‘re wasting your ad budget 💸"
    • "Calling all tech geeks and gadget lovers"

Example: Phrasee – "↓ Price Drop Alert 📉 "

  1. Poke fun at a relatable pain point
    Empathizing with your audience‘s daily annoyances and struggles shows you understand them on a human level. Try referencing common frustrations in a humorous way:
    • "Because ‘what‘s for dinner?‘ shouldn‘t ruin your day"
    • "Stop email FOMO in 5 easy steps"
    • "Mondays are hard. We‘re making them easier."

Example: Zulily – "Deals that make us proud (unlike our nephew, Steve)"

  1. A/B test different approaches
    The only way to know for sure what resonates with your specific audience is to test, test, test. Most email service providers make it easy to A/B test different subject line variants and analyze results. Test elements like:
  • Length (short vs long)
  • Emoji use (emoji vs no emoji)
  • Capitalization (sentence case vs title case)
  • Personalization (basic merge tag vs none)
  • Type of benefit (monetary vs non-monetary)

No matter how many "best practices" you read about, your audience is unique. Let your data guide you to the subject line elements that work best for your brand.

  1. Use timely references
    Capitalizing on big events, seasons, holidays, or pop culture moments can help your emails feel relevant and in-the-moment:
    • "28 Halloween costume ideas for marketers"
    • "How to achieve your [current year] fitness goals"
    • "Stranger Things have happened… like these deals"

Example: Grubhub – "Last Day To See Star Wars: The Force Awakens In Theaters"

  1. Ask for the reader‘s opinion
    Looking for an easy engagement win? Ask recipients for their feedback or insights. People love sharing their opinions, especially if it helps guide your future content or offerings:
    • "Tell us: What content would you like to see more of?"
    • "We want to hear from you! Take our 2-min survey"
    • "Which product are you most excited about? Vote now"

Example: Simple – "Why you bank – we want to hear from you"

  1. Give a clear command or CTA
    Your email has a goal – to drive a specific action. Your subject line can get readers in the right frame of mind before they even open the email. Use clear, actionable language that aligns with your CTA:
    • "[Name], your free gift is waiting. Open now"
    • "Start your 30-day trial today"
    • "Reserve your spot for [event] before it‘s too late"

Example: The Hustle – "Pay for Postmates with Uber Cash"

  1. Tease exclusive content or offers
    Everybody loves feeling like an insider. Give your subscribers VIP status by teasing gated content, waitlist access, members-only perks, or first dibs on a new product:
    • "An exclusive offer, just for our loyal customers"
    • "Be the first to access [blank] before we go live"
    • "Shhh! Nobody else has seen this sneak peek"

Example: Rent the Runway – "You‘re invited: Exclusive access for Rent the Runway members"

  1. Incorporate user-generated content
    Featuring user reviews, success stories, or social media posts in your subject line is an instant credibility booster. It provides valuable social proof that helps establish trust before people even open the email:
    • "Sarah saved $7600 on her taxes. Here‘s how…"
    • "See why 15,000 marketers love [tool]"
    • "This CEO doubled revenue in 6 months with [blank]"

Example: Pure Cycles – "1,479 five-star reviews don‘t lie"

  1. Localize for relevance
    If your audience spans multiple regions, try incorporating location-specific elements into your subject lines. This could be a city name, a local event, or even a reference to the weather forecast:
    • "[Name], are you ready for a heatwave in [City]?"
    • "Where [City] locals go for the best [blank]"
    • "Hey [Pittsburghers], we‘re coming to you!"

Example: Hinge – "See who‘s new on Hinge in Los Angeles"

Emerging trends for 2023 and beyond
As we enter 2023, technology and consumer expectations continue to evolve at a rapid pace. Keep an eye on these email marketing developments:

The impact of AI on subject line optimization
Artificial intelligence tools like language models and content generators are becoming more sophisticated and accessible. Many email marketers are already experimenting with using AI to craft high-performing subject lines at scale.

Brands like Chase, Vodafone, and Virgin Holidays have used AI to generate and optimize email subject lines, seeing significant uplifts in engagement metrics. The key is striking the right balance between machine efficiency and maintaining your unique brand voice. Expect to see more AI integration in email marketing tools in the coming years.

Hyper-personalization and data privacy
In a world of increasing data privacy regulations like GDPR and CCPA, marketers need to be smart about how they personalize email subject lines. Collecting and using subscriber data is a privilege, not a right.

Focus on providing value with your personalization efforts, not just inserting a name field. Use the data you have on customers‘ interests, behaviors, and preferences to craft subject lines that are hyper-relevant to where they are in the buyer journey. Just make sure you‘re being fully transparent on how you collect and use data, and always give people the option to opt out.

The dominance of mobile-first email
Over 70% of workers now use their mobile device to check email. That means your subject lines need to be concise, compelling, and easy to read on smaller screens. Stick to 30 characters or less and put the most important words at the beginning.

Also consider how your subject line will look next to your sender name and preview text in the mobile inbox. Does it create a cohesive message that stands out? Make sure to test your emails on multiple devices and email clients before hitting send.

Integration with omnichannel campaigns
Email may be one of the oldest digital marketing channels, but it‘s still a crucial touchpoint in a holistic, omnichannel customer experience. Make sure your email subject lines align with the messaging and creative your audience sees on your website, social media, paid ads, and other channels.

Consistency breeds familiarity and trust. For example, if you‘re running a holiday promotion across multiple channels, use similar phrasing in your email subject line as you do in your Facebook ads and Instagram posts. This creates a seamless experience as subscribers move from channel to channel.

Testing, always testing
Perhaps the biggest subject line "trend" for 2023 is… that there is no one-size-fits-all trend. The most effective subject lines are those that have been tested and optimized for your unique audience and goals.

Implement a consistent A/B testing process for your subject lines, trying out different lengths, tones, value props, and personalization elements. Let your data tell you what works, and don‘t be afraid to think outside the "best practice" box.

You can even survey your audience to understand which types of subject lines resonate best with them. Do they prefer straightforward or clever? Short and punchy or longer and descriptive? Gathering this kind of feedback is a great way to provide a more tailored experience.

Putting it all together
In a world of crowded inboxes and dwindling attention spans, investing the time to write irresistible email subject lines is non-negotiable. Treat your subject line as the front door to your email marketing efforts – you only get one chance to make a great first impression.

Remember, the goal isn‘t just to get the open. It‘s to deliver on the promise of your subject line and provide value to your audience with every email you send. Focus on building real relationships, not just driving vanity metrics.

As we continue into 2023, keep a pulse on emerging technologies and consumer preferences, but don‘t get distracted by shiny tactics. Ground your email subject line strategy in timeless, proven principles: know your audience, test everything, and always provide genuine value.

By combining data, creativity, and a relentless focus on your customer, you‘ll be able to craft subject lines that cut through the noise and drive real business results. Here‘s to your email marketing success in 2023 and beyond!