Write effective subject lines

1. Determine the target audience segment for this subject line by considering the email's content, goals, and buyer personas.

Email segmentation helps relevant messaging get to the right person. Subject lines can be segmented, like Good news! Another webinar is coming soon, for someone who went to your last webinar versus Investing webinar this Thursday, for a new lead. Some emails should only be sent to one audience segment, like an abandoned cart email or member-only coupons. Segment your email subscription list by: Persona. Profile-level: Like location or member status. Behavioral: Like automated triggers or interaction history. Position in buyer’s journey.

2. Determine the subject line's style based on the topic, format, and audience.

Think of an email subject line like the title of an article. It should match the content and engage the audience.  Consider breaking news, how-to content, and personalized messages. For informational, list-style content, the subject line could be 5 must-have pieces for your fall wardrobe.

3. Brainstorm at least 10 subject lines that contain elements of curiosity, urgency, relevance, value, or emotion, are around 9 and 60 characters, and are personalized for the audience.

Examples: Curiosity: Skillshare: See what’s launching this Sunday. Urgency: Investing Webinar: Only 5 Spots Left! or Last chance to get 50% off. Relevance: Hey Pittsburgh, BIG savings on flights this week. Value: Joe, your May product recommendations are here. Emotion: 4 Dangers to Your Pet You Don’t Know About. Since studies show around 55% of emails are opened on mobile devices, try to stick to around 5 or 6 words. Emails can be personalized by name, postal location, birthday, browsing, or transaction history. Use data from email opt-in forms, your CRM, and transaction history to supply this information. Many email marketing platforms, like GetResponse, can populate personalized fields.

4. Choose 2 or 3 subject lines to A/B test that vary by one quality, like length, personalization, rewording, or humor level.

A/B testing allows you to test subject line effectiveness by randomly sending one subject line to part of your subscription list and another to a different part of your subscription list. It’s unnecessary to A/B test every time, but it does collect data that helps you better understand and reach your audience.  For example: Personalization: Thanks for joining us, Beth vs. Thanks for joining us. Rewording: What’s next for AI? vs. 3 things to know about the future of AI.

5. Check chosen subject lines for common spam triggers, and run through a spam checking tool like mail-tester.

Common spam triggers in subject lines: All capital letters. Special characters or more than 3 emojis. Starting with RE: or FWD: Exaggerated claims like 100% free or free money. Deceptive language.

6. Use an email marketing platform to set up A/B testing and send emails.

Choose an email marketing platform that follows deliverability best practices, allows A/B testing and audience segmentation, tracks metrics, and offers automation. Some popular email marketing platforms are Mailchimp, GetResponse, ActiveCampaign, and Sendinblue.  Email deliverability is affected by:  Sender reputation. Use tools like Sender Score to check your sender reputation. No permission or authentication. Spam complaints. Email volume. Content, like too many images, suspicious links, or hidden HTML. Metrics.

7. Track metrics, including open, click-through, click-to-open, conversion rates, and generated revenue, to choose the A/B test winner.

Most email campaign software has built-in analytic tools. The winner of the A/B test depends on your objectives. For example, if your main goal is to have people read the information in the email, then the higher open rate is the winning metric.  Although A/B test wait time depends on your deciding metric, waiting 12 hours to a day before deciding the winner is generally recommended, especially for revenue results.

8. Measure overall subject line effectiveness by considering metrics, benchmarks, segmentation results, and marketing objectives.

In 2020, the average open rate across all industries was 18%, and the average click-through rate was 2.6%, according to Campaign Monitor. Your industry, business size, subscriber list, and length of time with an email marketing strategy, also matter when comparing to benchmarks. It’s useful to record all experimentation winners in a shared file with its metrics.

9. Continue to experiment with subject lines, monitor metrics regularly, and test other email variables to meet your goals.

Other factors may affect your email metrics and require separate A/B or multivariate testing or adjustments: Time and day of email delivery. Email content. Audience segmentation strategy. Deliverability health. When writing your next subject line, use the A/B test winner as a style guideline if you were satisfied with its metrics.