5 Subject Line Strategies for Your Email Campaign

When crafting email campaigns, the subject line remains the single most critical element determining whether our message gets opened or ignored. Whilst following email marketing best practices across your entire campaign matters, recent industry data shows that 47% of email recipients decide whether to open an email based solely on the subject line, whilst 69% report emails as spam based on that same line of text.

After years of testing and optimising email campaigns across various industries, we’ve refined our approach to subject line creation. These five strategies consistently deliver higher open rates and better engagement metrics for our clients.

Avoid overly sales-driven language

Regardless of whether you are sending out a newsletter or product-focused mailer, try to keep your subject line from sounding like you’re pushing the recipient to purchase. For example, instead of demanding ‘Buy our product now!’ why not try suggesting ‘Check out our latest product’. This small change makes customers feel less pressured and more likely to click on your email.

Regardless of whether you’re sending out a newsletter or product-focused email, avoid subject lines that sound overly promotional or pushy. Modern consumers are savvy and can spot aggressive sales tactics instantly.

Instead of demanding “Buy our product now!” try a more value-driven approach like “Discover how [product] can save you 5 hours per week.” This reframes your message around the customer’s benefit rather than your desire to make a sale. People are much more likely to engage with content that clearly offers them value.

Consider using language that:

• Focuses on solving a problem
• Highlights a specific benefit or outcome
• Creates curiosity without being misleading
• Speaks to the reader’s goals or pain points

Your content marketing strategy should extend to every touchpoint, including email subject lines that prioritise your audience’s needs first.

Keep subject lines concise and focused

Subject lines work best when they act as a preview rather than a full summary. The aim is to spark curiosity without overwhelming the reader or revealing too much too soon.

As a general guideline, keeping subject lines to around 40 characters helps ensure they are fully visible across devices, particularly on mobile where truncation is common. However, with approximately 81% of emails now opened on mobile devices, we often recommend aiming for 30-40 characters to guarantee the complete message appears on smaller screens.

Clear, concise wording increases the likelihood that the core message is seen and understood at a glance. 

Testing across different devices during the campaign creation process helps us identify how subject lines render for various audiences. The difference between a subject line that displays perfectly and one that gets cut off mid-word can significantly impact open rates.

Tailor language to your audience

Understanding your audience is essential when crafting subject lines. Generic subject lines generate generic results, whilst targeted messaging that speaks directly to recipient context consistently outperforms broad approaches.

If you’re communicating with a specialist or industry-specific audience, it may be appropriate to use terminology they are familiar with. This can signal relevance and expertise. For instance, a subject line for HR professionals might reference “Q1 retention metrics” or “hybrid working policies”, language that resonates with their daily priorities.

However, when targeting a broader or less informed audience, avoiding jargon is usually more effective. Plain, accessible language helps prevent confusion and ensures the message resonates with a wider range of recipients.

Be honest about email content

Subject lines should accurately reflect what the email contains. Misleading or exaggerated claims may increase open rates in the short term, but they often lead to frustration, higher unsubscribe rates and reduced trust over time.

Nothing damages sender reputation faster than deceptive subject lines. When recipients feel tricked into opening an email, they’re far more likely to mark it as spam, unsubscribe, or simply ignore future communications from us. The subject line should provide an accurate preview of the email content without giving away everything.

Use personalisation where appropriate

Personalisation can be a powerful tool when used correctly. Including details such as a recipient’s name, location or previous interests can help emails feel more relevant and timely. Research from Campaign Monitor shows that adding a recipient’s first name to a subject line can increase open rates by an average of 26%.

However, true personalisation goes much deeper than basic merge tags. Modern email marketing platforms provide access to rich behavioural and demographic data that enables sophisticated personalisation strategies.

Location-based personalisation might reference local events, weather conditions, or regional offerings. Behavioural personalisation can acknowledge browsing history, abandoned carts, or previous purchases.

Turning Subject Lines Into Meaningful Engagement

Email subject lines may be short, but their impact is significant. By focusing on clarity, relevance and authenticity, businesses can improve open rates while maintaining trust and consistency across their email marketing activity.

If you would like guidance on improving your email campaigns or broader digital marketing  marketing strategy, speak to our team about our solutions that support performance-led digital marketing.