10 testing variables to improve your email marketing

5 minute read

Once you have established a regular sending pattern for your email marketing, the next thing to think about is how to refine and improve your efforts. Here are ten variables to consider experimenting with, to find out which elements affect the engagement of your campaigns and help bring you the most traffic and return on your investment.

For most of the variables below you can use split testing to compare your results, but remember to test one variable at a time or you won’t be able to determine which factor made the difference.

Subject line

The subject line is the most obvious and easiest to test, as it’s the first thing the subscriber sees before opening your email. There are endless possibilities, for example comparing an informative announcement versus a more vague but intriguing approach to see which gets the best response. You could even see what happens when you include personalisation in the subject line.

From name

Investigate whether your campaign performs better if the ‘from’ name is an actual person, if the ‘from’ name is the company name, or whether including both works best. Once you’ve found what works, stick with to ensure your subscribers can recognise your emails easily.


Which header performs better for your business, a banner image or text? You could also try experimenting with the dimensions and colour of the header.


When it comes to personalisation the simplest thing to trial is whether inserting the subscriber’s name has a positive or negative effect, but you could take it much further by inserting custom profile fields or even introducing dynamic content.

Image placement

What happens if you change the layout of your images? Do your images attract more attention and drive more traffic when placed in a different position in your email? What happens when you increase or decrease the number of images? Don’t forget to keep a good balance of images to text to help the delivery of your campaign.

Call to action

A great ‘call to action’ will prompt your subscribers to interact with your campaign. Play around with placement, text and the design of your ‘call to action’ button.


Depending on your business, it is likely that an offer or incentive is going to gain more interest than solely informative articles. Adjusting the variation of content will help you find out what your subscribers really want to hear about.


Building a relationship with your subscribers is the goal and finding the right voice for your content and subject line can make a huge difference. What tone is most appropriate for your business?

Time of day

This isn’t something that can be tested via split testing, but sending the same campaign to different groups of people at different times of the day can return very insightful results.


Day of week

Testing the day of week is just as important as testing the time of day. Altering your sending day can improve or lessen your engagement, so it’s worth finding out the optimum day for your business.

There are a number of ways you can judge your results. If you’re using our split testing feature your results can be calculated by the highest number of opens or click-throughs, but you can also look at your campaign results to view the number of unsubscribes, shares and which links gained the most interest. If you have a Google Analytics account and have set up Google Analytics tracking on your campaign, this will give you further insight, as will our effective goal tracking API.

Remember, your results may not be 100% conclusive if there are only marginal differences, but regular testing can uncover patterns that will benefit your email marketing in the long run.