Email Design Mistakes That Hurt Deliverability & Engagement

Avoid These Blunders to Enhance Your Deliverability and Audience Connection

By Henry Timmes  ·  Email Deliverability Consultant  ·  Named contributor to RFC 7489 (DMARC)
Email DesignEmail TemplatesEmail Marketing
Henry Timmes
Henry Timmes Email Deliverability Consultant · Named contributor to RFC 7489 (DMARC)

In the world of email marketing, one small mistake can drastically affect your campaign's success. Marketing managers and co-founders share their top insights to help you avoid common pitfalls. Learn why keeping email design simple is crucial and how personalizing emails can significantly boost engagement. With five expert tips, this article equips you with the knowledge to enhance your email deliverability and engagement.

Marketing Manager DSMN8

Keep Email Design Simple

The biggest mistake I often see marketers make when it comes to email design is making it too complex and cluttered. Keeping it simple is key: What links or CTAs do you want readers to engage with? If there are too many links, fonts, colors, and images, your reader won't know where to look or click. Your email will take longer to download, too!

Optimize Your Email Images for Better Deliverability

One of my biggest email marketing mistakes was including high-resolution images without considering their impact on load times and deliverability. I created a beautifully designed newsletter featuring stunning product photos, thinking that higher quality would impress subscribers. Instead, the email took forever to load on mobile devices, and many images didn't display at all in certain email clients. The campaign had terrible engagement rates because recipients either couldn't see the content or got frustrated waiting for it to load. Worse yet, some email providers flagged it as spam due to the large file sizes. Make sure your images are optimized for size, compress images to under 100KB each, use web-friendly formats like JPEG or PNG, and always include alt text for accessibility. A well-optimized email that loads quickly will always outperform a beautiful one that doesn't reach the inbox.

Urban Idea

Co-founder & CEO FinlyWealth

Include a Clear Call-to-Action

One common misstep I've seen is sending emails without a clear call-to-action (CTA). The purpose can sometimes be lost if it's not explicitly stated what they're supposed to do next. As a recipient, you're more likely to engage with a simple, concise action step. Without this, they may feel confused or overwhelmed, which can lead to lower engagement rates. Always keep the CTA prominent and compelling.

Founder Smartlead.ai

Avoid Overloading with Heavy Images

One common mistake I've seen marketers make in email design is overloading emails with heavy images and graphics. While visually appealing, too many images can trigger spam filters, hurting deliverability. Plus, if your audience is checking emails on mobile or a slower internet connection, image-heavy emails might load slowly or not at all, leading to lower engagement. Instead, keep it simple: a balanced mix of clean, readable text with a few well-placed images works best.

For example, I've seen plain-text emails with personalized messaging outperform fancy designs time and time again, especially in cold email campaigns. Always prioritize clear communication over flashy designs - it can make all the difference in getting into the inbox and driving real engagement.

Co-Founder Hoppy Copy

Optimize Emails for Mobile Devices

I've seen my fair share of email marketing blunders, but one common mistake really stands out: neglecting mobile optimization. With so many people checking emails on their phones, designs must look great on all devices. If your email isn't mobile-friendly, you risk losing a significant portion of your audience right off the bat.

When emails are poorly designed for mobile, users may have to zoom in to read text or struggle to click links, leading to frustration and lower engagement rates. This can affect deliverability, as many email providers take engagement metrics into account when deciding whether to send your emails to the inbox or the dreaded spam folder.

To avoid this, I always recommend using responsive design techniques. This means your emails should automatically adjust to fit the device's screen size. Simple, clean layouts with larger fonts and buttons can make a difference. Keeping your content concise and visually appealing ensures that recipients can easily read and interact with your email, boosting engagement and ultimately leading to better deliverability. Remember, a little attention to mobile design can go a long way in email marketing!

Personalize Emails for Better Engagement

The most common email-design mistake that marketers make repeatedly, which impacts deliverability and engagement, is failing to personalize the emails.

Personalized emails with a name tag and tailored headline help the recipient feel seen by the entity sending the email. This can easily trigger them to click open the email and take the action prescribed.

It is important for marketers to research more about the recipients on their mailing lists. The objective should be to know their pain points, goals in life and business, and how your product or service can help them.

Such information allows you to tailor the emails to specific recipients with the help of automation tools, increasing engagement.

Cleaning up your email list is also crucial as a marketer to eliminate any unresponsive recipients and wrong addresses. This improves deliverability.

Design Mistakes Are Deliverability Mistakes

Many of the design mistakes experts flag above — image-heavy emails, missing alt text, broken links, oversized HTML — are also spam filter triggers. Good email design and good deliverability are the same discipline.

Campaign Cleaner catches rendering issues, oversized code, and content flags before they affect your inbox placement.

Emails Landing in Spam? Let's Fix That.

Henry Timmes is an email deliverability consultant and named contributor to RFC 7489 (DMARC). Book a free 15-minute call — no pitch, no obligation, just answers.

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