VWO Logo
VWO Testing
A/B Testing

A/B Testing Solutions to Maximize Your Website Conversions

Create and A/B test different versions of your website and its elements to continuously discover the best-performing versions that improve your conversions.

Know more
Complies with:
VWO GDPR Ready Badge
VWO CCPA Ready Badge
VWO G2Crowd Leader Spring Badge
Trustradius badge for VWO

We tweet useful stuff daily

Related content:

5 Parts of a Highly Converting Email – Analysis for Optimization

10 Min Read

When it comes to lead generation or customer communication, email marketing is still the preferred medium for a lot of businesses.

And, for good reasons.

  • Email marketing can help businesses generate 138% more revenue[1].
  • 60% of marketers report that their email marketing efforts produce healthy ROI.
  • Email even beats the most popular social media platforms[2] in acquiring customers.

However, email marketing can only be effective when you know how to draft near-perfect emails; the kind that users love to find in their inbox.

For that, optimizing each and every element of an email is a must.

In this post, we dissect and look at 5 email components, and find how to create flawless emails. Here are the components of a typical email you’ll find analyzed in this post:

  • Subject Line
  • Sender Name
  • Images Within Email
  • Email Copy
  • Call to Action

Let’s start.

Subject Line

The subject line of an email is, arguably, the most important factor for users to open an email. No matter how great your email content is, if the subject line doesn’t push users to open the email, it’s going to waste.

You should spend as much effort in mulling over the subject line of an email as you do while drafting the email itself. Here are some important factors to consider before writing a subject line:

Length of the Subject Line

It’s important to keep your subject line to an appropriate length. Too long a subject line runs the risk of not showing up completely in the user’s inbox. Too short a subject line might fail to communicate what the email has to offer.

While there’s no magic number for the most-effective length of a subject line, some studies give us a point of reference.

An article by Marketing Sherpa shows that subject lines with 41-50 characters are the most popular among marketers. It also shows that 61-70 characters deliver the highest read rates.

Subject line length and average read rate chart

Moreover, 40% of emails[3] are opened on mobile first.

It would be wise to use even shorter subject lines if your users are primarily on mobile. Be aware that the most popular mobile phones let you display only 31-40 characters of a subject line.

Employing Psychological Elements

Construct subject lines incorporating psychological triggers that influence a user’s behavior. Like the following:


You can build curiosity among users by not entirely revealing what the email has to offer in the subject line. This can impel users to open the email to find what’s inside. But use your discretion. Unless the user has reason to believe the action (opening the email) is going to reveal something worthwhile, your email will remain unread.

Curiosity can work well with your drip email campaigns, as users are aware of your brand and have context to your business.

For instance, Inbound.org taps on users’ psychology using interesting subject lines for its email campaigns. Here’s how it uses the curiosity factor:

Curiosity Factor In Email

Here, unless the user has an interest in buying posters, the twist doesn’t matter, nor does the email. Spot anything else wrong with the subject line? Yes, the wording. ‘50% off on everything’ is a juicy deal. That is followed with a ‘but’. Which tells the user that the offer is subject to some condition being met. Even worse, the condition itself isn’t revealed in the subject line. Bad copy. In all probability what they meant to say was that there’s a 50% off on everything AND something MORE is in store – ‘wanna know?’. Inadvertently, but surely, the ‘but’ killed this email.


You can use urgency in your subject lines to make users open your emails.

Offer lucrative deals to your users, with a limited time validity. Mentioning that on your subject line can compel users to open an email in an attempt to not miss the deal.

Find an example below:

Urgency used in email subject line


Offer personalized content, discount deals, or other exclusive incentives to some of your users. If the subject line mentions that the email contains something exclusive for users, they’ll feel valued and proceed to see what the exclusive offer is.

This is how Myntra, a fashion eCommerce store, employs it:

Exclusivity used in email subject line

Notice how the above email employs exclusivity and urgency together.

Testing Different Subject Lines

You cannot know beforehand about which one of your subject lines will perform the best.

A subject line that worked great for one business might fail for another business’ email. It all depends on your audience and what they crave.

But, you can find out what works best by A/B testing different subject lines for your emails.

Best subject lines and worst subject lines comparison

Sometimes, even the most plain subject lines can work wonders. Take a look at Mailchimp’s comparison[4] of the best and the worst performing subject lines.

Sender Name

Often, businesses use the company name, brand name, product name, name of a person, or simply an email address as the sender name for their emails. Quite apparently, not much thought is given in deciding the sender name. Perhaps, because it occupies much less space in inboxes compared to subject lines.

Ignoring sender names can cost businesses dearly.

The importance of an email’s sender name can be seen from the fact that 43% users report emails as spam just on the basis of their sender names.

The best choice of sender name for your emails should be what your users relate to the closest.

For big companies, using the brand name as the sender name seems to be an obvious choice. But, for smaller companies, using their founder’s name — who presumably has a greater reach — along with the brand name can lead to better email performance.

Take a look at this screenshot.

comparison of different sender names of email

The first email lacks any information about the brand name. The sender name and the subject line (and even the small preview text following it) doesn’t mention it. The email gives little encouragement to users to open it.

In contrast, the second email clearly communicates the brand name (Hubspot) and gives immediate credibility to the email.

Images Within Email

Images have become an essential part of emails today. 65% users prefer emails[5] that contains mostly images.

However, using images in emails require giving consideration to a number of factors.

Number of Images

How many images are too many images? This depends upon the type of the email, and the audience that you’re targeting. By looking at the performance of your previous email campaigns, you can figure out the number of images that your users are most comfortable with.

Nevertheless, Constant Contact reported[6] that emails with three or fewer images delivered the highest clickthrough rates.

Using Alt Tags

Many email clients do not show images within an email automatically. They require users to click on a “Display Images” button to show the images. When users don’t do that, they find an empty email devoid of images.

However, HTML alt tags can still help you display information in an email. For instance, “alt text” lets you display text in place of images, whenever the email client does not show images.

Using alt text for images in emails

Furthermore, you can use CSS to stylize the alt text to make them look better.

CSS used within alt text for images

Using Different File Formats for Images

There is a variety of file formats for images that you can use with your emails.

Out of them all, JPEG and PNG file formats are the most used across the internet. Both have their own advantages and drawbacks, and the choice should depend on your requirement.

Also, lately, the GIF format of “moving images” is getting popular to make emails more fun. Here’s an example:

GIF used in email

Below is a guide from Litmus[7] that will help you find the right image format for your emails.

Comparison chart for different image file formats for emails

Email Copy

An eye-catching subject line might deliver a big number of opens for an email. A few interesting images in an email might make users like it.

But if the email copy — the actual content — is ineffective, you won’t get clickthroughs and conversions. Delivering poorly written emails is a guaranteed path to miserable conversion rates.

Here are a few ways to ensure that your email copy is top-notch.

Write Scannable Copy

It’s well-established that web users don’t read anything on the internet completely[8]. Whether it’s an article or an email, users scan through, trying to identify valuable and snackable bits of content.

Your email copy should have scannable components that users can pick up easily.

  • Write short bulleted points.
  • Highlight your main content using contrasting colors.
  • Use phrases in place of whole sentences (while communicating the intended meaning).

Here’s an example:

Example of scannable email copy
Image Source[1]

Use Headlines with Discretion

You don’t want to confuse users with a ton of headlines within a single email.

With multiple headlines, users will find it confusing to understand the hierarchy of information ?— what’s most important and what’s not. Users won’t know what to focus on. The cursor drifts, and user is lost.

When your email contains only a few headlines, users’ attention is effectively directed towards them.

Avoid Spammy Words

There are certain words that can trigger spam filters of email clients, e.g., “free,” “money back guarantee,” etc.

Including such words excessively inside your email copy can send your emails to the dreaded spam folder. Use them sparingly.

Below are a few more spam words for your reference:

  • Visit our website
  • 50% Off
  • Click here
  • Call now
  • Subscribe
  • Bonus
  • Discount
  • Save up to
  • Prizes
  • Information you requested
  • Important information regarding
  • Guarantee, Guaranteed
  • Special Promotion
  • Great Offer/Deal
  • All New
  • One Time
  • Order Now

Want more? Here is an extensive list by SalesForce Pardot[9].

Clearly State The Benefits

More than the information on your product or service, users are interested in knowing the benefits they’ll receive from it. Your email copy must communicate benefits over features.

Take a look at this product update newsletter from Google Analytics:

Stating benefits clearly using email copy

Call to Action

So your users have opened your email and gone through its images and content. What next?

You need them to take some action on the email that translates to a conversion. The conversion can be anything based on your campaign: clickthrough to your website, a resource download, completion of an abandoned order, etc.

You can direct users to take such actions using a Call to Action (CTA) button.

Follow the below practices to make your CTA button stand out.

Minimize Number of CTAs

Your emails should have just a single goal to fulfill (else it is an email with no definite purpose), it should contain only one (or at most two) CTA buttons. This helps users easily identify the CTA, increasing the chances of a conversion.

For example, Whirlpool reduced the number of CTAs[10] in one of its email from four to just one, and achieved 42% more clickthroughs.

Single CTA in email copy (example)
Whirlpool’s email with a single CTA button

Make the CTA Visible

Perhaps, the most important attribute of a CTA button is its visibility.

If your CTA button blends in with the background, it is as good as plain text of your email.

Ideally, your CTA button should have sufficient white space around it, and it must carry a contrasting color to the background.

Here’s an example of a clear email CTA button from Canva.

Example of a clearly visible CTA

Use Actionable and Relevant CTA Copy

The CTA buttons within your emails must be directly related to your email’s purpose. The CTA copy should effectively communicate the specific action that the email wants users to take. By using an actionable phrase, you can push users to go for that conversion.

Here is an excellent example. The CTA says ‘Shop Loafers’. Talk about simplicity.

clear and relevant CTA in email copy

Related Post: Call to Action Buttons: The Ultimate Guide on Which Ones Convert and Why

Ready To Optimize Your Marketing Emails?

Use these tips to optimize your marketing emails and boost conversions. Do not forget to let us know about your success stories.

Also, if you have anything to add to this article, please write to us at marketing@vwo.com

More from VWO on Customer Engagement
3 Key Aspects of Engaging Consumers on Your eCommerce Website

3 Key Aspects of Engaging Consumers on Your eCommerce Website

The online shopping experience is incredibly dynamic. In many ways, shopping on the internet is…

Read More
David Rosenfeld

David Rosenfeld

15+ Min Read
2020 B2B Marketing Landscape: What’s Changing

2020 B2B Marketing Landscape: What’s Changing

2020 marks the start of an exciting decade for B2B marketing.  Developments in AI and…

Read More
Mukesh K. Singhmar

Mukesh K. Singhmar

5 Min Read
What is Marketing Automation? How Does It Help?

What is Marketing Automation? How Does It Help?

According to the IDC, the amount of accumulated data in the digital universe will grow…

Read More
Shubhi Ahluwalia

Shubhi Ahluwalia

11 Min Read

Scale your A/B testing and experimentation with VWO.

Start Free Trial Request Demo
Shanaz Khan from VWO

Hi, I am Shanaz from the VWO Research Desk.

Join our community of 10,000+ Marketing, Product & UX Folks today & never miss the latest from the world of experience optimization.

A value for this field is required.

Thank you!

Check your inbox for the confirmation mail