What should you test in your email campaigns?

Many people believe the only item you test in an email campaign is the subject line, and while it is the most popular, there are tons of possibilities.

I’m listing a few ideas of items you can test in your campaigns, just remember, one test at a time…

To make this in an organized way, let’s categorize them in 5 groups:

  • Subject line and other items in the preview
  • Timing
  • Content
  • Image (should be part of content but…)
  • Call-to-action

Some of these groups represent many more testing options than others, like content versus timing, it’s not because we ran out of ideas.

Ready? Let’s go then!

Subject line & Preview

Subject line

You know the subject line is the most tested item in email marketing. Let’s see a few things you can test to get more opens:

Personalization vs. No personalization:

  • “@socialmouths, your Twitter account has grown!”
  • “Your Twitter account has grown!”

Long vs. Short:

  • “NEW: How to Use a Webinar to Make $11K with a Fedora Course (Guest Post from Scott Britton)”
  • “How to make $11k in course sales in one webinar”

Branding vs. No branding

  • “Single Grain Weekly News: The Latest From Our Blog and Around the Web”
  • “Weekly News: The Latest From Our Blog and Around the Web”

Statement vs. Question:

  • “You’re looking for reach, engagement and sales in all the wrong places”
  • “Reach, engagement, sales. Are you looking in all the wrong places?”

Positive vs. Negative:

  • “How to grow your Facebook page faster”
  • “This is why your Facebook Page is not growing”

Special characters:

  • “60+ Fantastic Email Newsletters to Read and Share”
  • “60+ Fantastic Email Newsletters to Read and Share 😉


  • “free”
  • “freebie”

Offer language:

  • “20% Discount”
  • “Save 20%”


  • “20% Off”
  • “$30 Off”


  • “Happy Monday – Download 6 New Free Goods”
  • “Happy Monday – Download 6 New Free Goods!”


  • “Happy Monday – Download 6 New Free Goods!”
  • “Happy Monday – Download 6 New FREE Goods!”

You’re probably asking yourself why I didn’t include “Ambiguity vs. Relevancy.” There’s a reason, I think ambiguity can lead to a sense of being misled in some cases. So I don’t test it.

Pre-header text

Since the pre-header is basically a line of text similar to the subject line, most tests you can run on subject lines can also be applied to pre-header text.

For example, think about the possibility of using personalization in the pre-header text instead of the subject line.

From name 

Branding vs. No branding:

  • “Francisco (from SocialMouths)”
  • “Francisco Rosales”


  • “Francisco (from SocialMouths)”
  • “SocialMouths”

And, of course, “From email address” can also be tested.


There are very few things to be tested when it comes to timing…

Day of the week:

  • Friday 
  • Sunday 

Time of day:

  • 12pm
  • 2pm

Individualized Send Time vs. Universal Email Send Time:

  • Send all on Friday at 11am PST
  • Send Friday 11am based on individual zones

Time of day (individual subscriber’s time zone):

  • Friday 11am (UTC)
  • Friday 2pm (UTC)


In your content, there are many more items you can test, I’ll skip the ones we already mentioned.


  • “Hey!”
  • “Hey John,”

Bullet points vs. Paragraphs

Bullets make content more scannable and can increase engagement in your campaign. Test using laser-focus bullets instead of paragraphs.

Call outs:

If you’re offering a product that is specific to a group of people, let’s say freelancers, test call them out against generalization. This could result in more conversions from that specific group or people while others disqualify themselves.

Placement of elements:

  • Featured product and then offer
  • Offer and then featured product

Social media:

With social profile links you can test different options…

  • Icons
  • Links

Or simply the positioning.

Short vs. long:

  • Short copy
  • Long copy

Number of links:

  • 1 link
  • 2 links


  • Add a PS
  • No PS


  • PS with a link
  • PS without link


  • 1 testimonial
  • 2 testimonials


  • Testimonial at the bottom
  • Testimonial in the middle

or simply…

  • Testimonials
  • No testimonials


Use of images:

  • Image
  • No image

Number of images:

  • 1 image
  • 2 images


  • Image at top
  • Image in the middle


  • Static (JPG or PNG)
  • Animated (Gif)

Hero shot vs. “in use”:

  • Hero shot of the product
  • Product in action

Personalizing images based on customer profile:

If you have data like gender, you can test different images to appeal to each of them.



  • Button
  • Link

Repetition of CTAs:

  • 1 CTA
  • 2 CTAs


  • “Reserve your spot now”
  • “Reserve your spot today”


  • Above the fold
  • Below the fold


  • Center aligned
  • Left aligned

Very important

There is no homework here, and if you’re looking at this list to see if you pick one of these ideas to test… Stop.

Remember hypothesis? This list of ideas is not for you to get inspired to test things. Instead, use it once you have a goal and a hypothesis in your hands.

Example: You need to increase your open rates, you have been testing subject lines but you still feel you can make a bigger impact. You hypothesis is that, since you have a global audience, some of these folks are receiving your campaigns at the intended hour, but some are getting them in the middle of the night, if you optimize delivery times, you can increase opens.

Now you can look at this handsome list and go: “hey, let’s plan a series of tests to optimize timing. First, based on our current data, and then we can test individual time zones.”

Get it?