Mastering email marketing: Metrics that matter
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Email remains one of the most powerful and cost-effective marketing channels (if you use it right). With inboxes more crowded than ever, success depends on mastering the art of relevance, timing, and measurement. Here’s how to refine your email strategy, track the right numbers, and experiment your way to higher engagement.
1. Start with segmentation
Don’t batch and blast to your database. Segment your audience based on purchase history, browse history, demographics, or behaviour on your site. Personalisation increases open and click-through rates dramatically… especially when messages align with the customers’ interests. Studies have shown that personalised emails can increase conversion rates by up to 60%.
Segmentation really helps you understand your customers and how they will respond.
Key segments to build:
- Vip/ top spenders
- Most engaged – browsed last 30days
- Recent purchasers
- Lapsed customers
- Winback
- Seasonal shoppers
- Birthday/Anniversary
2. Craft a clear and compelling subject line
Your subject line is your first impression. Keep it short, personalised & relevant. Ensure you entice your customers to open. Keep it under 50 characters. Avoid spammy words (“free”, “act now”) and instead focus on clarity and curiosity. Always pair it with a strong preview text to reinforce the message.
Subject Line: Welcome to the family, here’s 10% off your first order
Preview Text: As a thank you, here is 10% off as a special thank-you gift.
Subject Line: Your favourites are back in stock
Preview Text: Be Quick- limited stock won’t last long.
3. Optimise for mobile
Over 60% of emails are opened on mobile devices. Use responsive design, concise copy, and clear CTAs that are easy to tap. Test across devices to ensure consistency.
When your emails look great on any device, your chances of conversion go up. After all, nothing kills engagement faster than an email that won’t load. It’s a quick path to unsubscribes and spam reports.
4. Prioritise value over volume
Quality over quantity. Every email should have a clear purpose: educate, inspire, or drive action. If you’re over-sending to your audience with messages, offers or products they are not interested in they will switch off to your emails; however, if you send fewer, more personalised emails, they will take the time to engage and read with them as they bring value, and the customer will want to hear about what you are saying rather than being overwhelmed.
5. Include a single, strong call-to-action
Ensuring your email has a clear CTA, ensures the reader knows what you are trying to drive them to do. If your email is too busy the reader could become overwhelmed and disengage. Keep your emails short and concise so they click to the main site for more information. Every email should guide them toward one primary action, whether it’s to download, shop, or learn more.
Key metrics to keep an eye on
Understanding what success looks like starts with tracking the right data. Here are the core metrics that really matter:
Since Apple’s iOS privacy updates, open rates aren’t as reliable as they used to be. These days, you need to look at other metrics and focus on clicks, conversions, and engagement trends.
Click-Through Rate (CTR)
Measures how engaging and relevant your content is.
Benchmark: 2–5%
Conversion rate
The percentage of recipients who take the desired action (purchase, sign-up, etc.).
Benchmark: 1–3% for most industries
Open rate
Indicates how compelling your subject lines and sender names are.
Benchmark: 20–30% (depending on industry)
Bounce rate
Shows the quality of your email list and data hygiene.
Keep it under 2%.
Unsubscribe and Spam Complaint Rates
Monitor audience fatigue and relevance.
Keep unsubscribes below 0.5% and complaints below 0.1%.
Revenue per Email (RPE)
The ultimate measure of ROI.
Track how much each email contributes directly to sales.
A/B tests every marketer should run
Key A/B tests you can start with to see how you can improve your engagement would be the below
- Subject line
- Timing
- Content style
- Design
- Personalisation level
Subject line testing
The subject line is your first impression. Small tweaks can make a big difference in open rates.
Example:
A: “Your Exclusive Offer Inside”
B: “Jane, Here’s 20% Off Just for You”
Content
Short emails drive faster engagement, while long-form emails build trust and can improve conversions. Testing helps you discover your audience’s content preference.
Example:
A: 75-word email with one clear CTA
B: 300-word email with storytelling, proof points, and context before the CTA
Send time optimisation
Timing can dramatically impact visibility and engagement, especially for audiences in different time zones or work patterns.
Example:
A: Tuesday, 10 AM send
B: Thursday, 4 PM send
Successful email marketing blends data, creativity, and iteration. By following best practices, tracking performance with meaningful metrics, and running smart A/B tests, you can continuously refine your approach. Emails that feel personal, deliver value, and drive measurable results.
