Five Email Marketing Mistakes
Even Smart Companies Make (and How to Fix Them)
Email is still one of the most powerful tools available to marketing teams today. It supports every stage of the buyer’s journey, increases customer engagement, and delivers proven ROI. Despite its widespread adoption and use, even the most experienced marketing teams still make common mistakes that undermine the impact of even the most sophisticated email campaigns.
Yet there is some good news. These email marketing mistakes are all fixable. In this article, we’ll take a closer look at five of the most common missteps smart companies still make today – and how to correct them before they affect your performance and overall results.
1. Sending to the Entire List Every Time
The mistake:
Many brands default to the “same old, same old” approach: sending batch-and-blast emails with the same message to their full list, regardless of the audience’s behavior, preferences, or position in the funnel. While this might maximize reach, it rarely delivers the right results.
Why it happens:
Let’s face it: most marketing teams are under a lot of pressure. With deadlines coming up fast, personalization and segmentation often get pushed to the back burner.
Why it’s a problem
Your customers aren’t all the same. For example, some haven’t opened an email in months while others are loyal buyers. Treating them identically can lead to disengagement, unsubscribes, and a dip in deliverability.
How to fix it:
- Use segmentation to group subscribers by behavior, demographics, or engagement level.
- Incorporate dynamic content to tailor messages within a single email based on audience traits.
- Develop and execute automated workflows and experiences based on customer actions (e.g., browsing a product or abandoning a cart).
Bonus tip:
Most email service providers (ESPs) offer powerful solutions and capabilities to make this easier than ever, helping marketing teams increase engagement and retention.
2. Neglecting Mobile Optimization
The mistake:
Sending beautifully designed emails that look great on a desktop but deliver the same experience on smartphones and mobile devices (if they even work at all).
Why it happens:
Marketers often build and preview emails on their laptops, not realizing just how different the experience is on a small screen.
Why it’s a problem:
According to Hubspot, 46% of email opens happen on mobile devices. (For more insightful email marketing statistics, check our article, Email Marketing Statistics Every Marketer Should Know.) If your email isn’t optimized, it may load slowly, display incorrectly, or, worst of all, could be completely ignored.
How to fix it:
- Use responsive design that adapts to all screen sizes.
- Stick to a single-column layout with readable fonts and tappable buttons.
- Preview and test emails across devices and clients before you hit send.
If your ESP offers mobile previews or automated testing tools, make them a standard part of your QA process.
3. Overlooking the Subject Line and Preheader
The mistake:
Writing and designing a great email but not dedicating as much time to the subject line and preheader.
Why it happens:
Many marketing teams tend to write subject lines as the last part of the process or when they’re under time pressure. There’s a real science to coming up with more effective subject lines, yet too many teams pull them from a campaign brief or other source with little testing or variation.
Why it’s a problem:
Your subject line and preheader are your first (and sometimes only) chance to get your target audience to open your email. One thing we know for sure: A weak one leads to lower open rates – no matter how good the content inside.
How to fix it:
- Write multiple subject lines and continue to test them (A/B testing is essential).
- Use personalization, curiosity, urgency, and other creative approaches.
- Don’t forget the preheader. Think of it as your second headline: it should complement or expand the subject line to communicate more information and encourage clicks.
A/B testing tools built into your ESP can help identify what resonates with your audience and improve open rates over time.
4. Focusing on Vanity Metrics
The mistake:
Chasing open rates and click-through rates without measuring what really matters – conversions, long-term engagement, and revenue.
Why it happens:
These top-of-funnel metrics are easy to track and often look good in reports. But they don’t always correlate with business results that actually move the needle.
Why it’s a problem:
Think of it this way: You might celebrate a campaign with a 45% open rate and 8% CTR – but if it didn’t lead to any sales, signups, or meaningful action, was it really that successful?
How to fix it:
- Define clear goals for each email — whether it’s purchases, downloads, bookings, or replies.
- Track post-click behavior using UTM parameters and integrations with your analytics platform or CRM.
- Consider using attribution modeling to understand how email contributes to the customer journey.
Today’s ESPs often include revenue tracking and goal-based reporting, so make sure your team is using those tools to align campaigns with business objectives.
5. Skipping Regular List Hygiene
The mistake:
Holding on to inactive or unengaged subscribers indefinitely, in the hopes they’ll come back around.
Why it happens:
No one likes to see their list shrink. Plus, it takes effort to create and maintain suppression rules or re-engagement workflows.
Why it’s a problem:
Yet a bloated list with low engagement hurts your sender reputation and actually reduces email deliverability, which means that fewer messages reach your audience’s inbox.
How to fix it:
- Regularly remove or suppress inactive users (e.g., no opens or clicks in 6–12 months).
- Run re-engagement campaigns to try and win them back before removing them.
- Use your ESP’s engagement tracking to automate this process – flagging unengaged users and segmenting them for targeted outreach.
Smarter, More Effective Email Marketing Starts Now
Even the best marketers can fall into these traps, especially when juggling tight timelines, multiple campaigns, and evolving business goals. But fixing them doesn’t require a complete overhaul. With the right strategy and support from a capable email service provider, brands can build smarter, more effective campaigns that truly connect with their audience.
By segmenting thoughtfully, optimizing for mobile, perfecting subject lines, focusing on meaningful metrics, and keeping your list clean, you’ll not only avoid these common mistakes – you’ll outperform brands still stuck in the old habits.