9 secret content strategies to improve email deliverability

March 23, 2020
email content strategies to improve your email deliverability

Did you know with just a few tweaks you can improve email deliverability much more quickly?

Email inbox is a delicate destination, where only the strongest emails arrive, let alone survive. 

With average email open rates for 2020 hovering between 17- 20%, improving email deliverability and user engagement are some of the biggest challenges faced by email marketers. 

Well, if no one opens your emails, what’s the purpose of sending them? And, if your promotional emails land in spam or disappear into the mysterious black hole, what’s the point?

91% of cyber attacks begin with a phishing email- according to a 2017 study by Digital Guardian. Globally, 6.4 billion fake emails (sent from fake From: addresses) are sent every day according to the Email Fraud Landscape Report.

If marketers know about the power of email as a medium, so do fraudsters.

No wonder email inbox placement and email deliverability are getting more complex by the day. 

Mailbox providers consider many factors for placing an email in the inbox. 


Secret content strategies to improve email deliverability are here.

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Here are some of the factors that affect email deliverability:

  •  When email authentication is void

When major MBPs (Mailbox Providers) look into an email, they trace the origin of the email, look into email authenticity and ensure mails have not been altered in transit. So, it is vital that proper domain configurations (DKIM, SPF, DMARC, FBL, PTR, RDNS) are in place before sending out campaigns.

  • When sending IP flagged by major blacklisting agencies

Sender reputation is a combination of IP and domain reputation. If IP loses its reputation, it can affect delivery drastically. We have seen fall in open rate when IP reputation is bad in GPT (Google Postmaster Tool) and when IP gets listed by major blacklisting agencies like (Spamhaus, Proof point, Barracuda, Spamcop, etc.)

  • When domain reputation gets affected

Domain reputation plays a vital role in inbox placement as it attributes the reputation score which is assigned by the MBPs. Major MBP like Gmail strictly look into the domain reputation of the sender and decide where to place the emails.

  • When engagement metrics fall

MBPs rate the sender’s reputation based on the engagement of the email sent to customers. Good email engagement is directly proportional to sender reputation.

  • Poor maintenance of list hygiene

Maintaining list hygiene is pivotal to keep IP/ domain reputation and engagement metrics intact. Failure in maintaining the highest level of list hygiene would eventually lead to compromises in inbox placement with bigger MBPs. Be aware that in old inactive email list data, it’s possible for some email ids to have turned into spam trap (honey pots) emails. Sending emails to traps would lead to major deliverability issues and would lead to a total show stopper.

  • Poor content management

Smart email content management strategies and tricks are vital to create good email content that in turn improves email deliverability.

You may be an expert in email marketing. You may know industry-best email marketing practices like the back of your hand. But it’s still not necessary that you get good inbox placement. 

Email marketers should smartly manage email content and deploy necessary testing strategies to choose the best-performing content. 

Here are a few content tips for email marketers to improve email deliverability and inbox placement.

1. Subject line matters

Nearly every inbox is bombarded with hundreds of emails. Industry statistics indicate that anywhere between 45 to 50% of emails a person receives is spam. 

If you need proof- you only need to open your own mailbox and spam folder and do a random check. 

With so many spam emails, it’s not surprising that email users face the needle-in-a-haystack situation every time they open their inbox. 

How do they decide if a particular email in their inbox is relevant or not? How do they take a call – to delete, open or mark as spam?

For identifying an email as relevant or irrelevant, users look at subject lines. We know from experience that it’s common for recipients to look at email subject lines and upon finding them irrelevant, delete the mails or mark them as spam? 


1.1. Do not Mislead: A subject line should be in line with the message conveyed in the mail. It should not mislead the user by making fake claims or false promises.

If the subject line doesn’t look relevant to email recipients, it’s possible that they report the email as spam, not open it or press the trash button! 

1.2 Keep it Crisp: Stick to the prescribed number of characters in the subject line rather than trying to include everything- right from the brand name to offers and the rate tag. 

It’s better to keep the subject line below the recommended 40 characters and avoid using multiple special characters. There is a high chance for ISP filters to sieve your message and mark it as “This message seems dangerous”



1.3 Say Goodbye to the Sales Line: – It’s better to go easy on promotional trigger words like offer, discount, free, hurry etc. After removing sale tags from the subject line, we have seen mails move to the primary folder in ISPs like Gmail. 

There is a greater possibility of mails landing in the promotional tab if an overdose of promotional words are used in the subject line. As many overtly promotional email subject lines come with an embarrassing barrage of numbers and symbols along with promotional words, it’s possible that users dismiss your emails as spam even before they open it.

Below is a campaign performance analysis for one of our clients where promotional and non-promotional subject lines were used to target the same user base.

Using non-promotional subject lines helps in better email inbox placement and increases the probability of the email landing in the primary mailbox tab.

The basic lesson here is – don’t look like a spammer!

Steer clear of spammy words and phrases like “Jackpot”, “50% off”, “WINNER!”, “$$$ Affordable” or “100% Free”. Unless absolutely necessary, stay away from special characters ($%#), and always double check your copy for correctness of spelling and grammar.

2. Reply-to Address (Don’t use no-reply)

It’s observed that users prefer to reply to the email address from which the mail was sent. More replies indicate better email engagement which in turn leads to better email deliverability. 

Using the “no-reply” address is considered a bad practice as users are not encouraged to respond. Gmail’s updated sender guidelines recommend using separate reply addresses according to the mail streams (i.e., receipt@your-company.net, deals@your-company.net, alerts@your-company.net) etc.

From address needs to be classified based on the communication intent:

 Billing messages: billing@domain.com

Order updates: updates@domain.com

Notification messages: alerts@domain.com


3. Sender Authenticity is Important

Sender name is one of the most important factors that influences email recipients – from opening, deleting or marking an email as spam. Email users look at the sender name and make assumptions regarding the sender authenticity. 

The sender names can make or break the email campaign performance matrix.  

There is a misconception that spoofing a sender name could help increase the open rate and get better engagement. This might help to get a higher open rate but there is a greater probability for the user to mark the email as spam when they realize that they have been misled. 

It’s recommended to add the brand name in the “From” field. It helps users recognize the brand.

Spammers with low or poor email sending reputations and/ or who use purchase/ un-confirmed opt-in lists deploy these fraudulent mailing practices.


4. Personalize the content

Pause for a moment and take stock of how many emails you receive every day. 50? 100? Or, more? 

When you receive showers of emails every day, personalising emails would help stand out and obtain good results. 

Personalising content is a smart strategy to strengthen ISP-wise reputation and creates more value to the marketer. 

If marketers can deliver what the user expects, it’d eventually create more engagement with the mailer content. 

Use of personalisation makes your email stand out from regular promotional content and chances are ISPs would treat it as personal communication. 

All these would  help your emails bypass mail filters of ISPs like Gmail. This helps gain more  engagement with your emails and goes a long way in building strong ISP relations. 

5. Avoid shortened URLs

Shortening helps to reduce the length of URLs but unfortunately, they are also used by spammers for masking the links. 

URL shortening is one of the tools used by spammers to hide their malicious website and domain from ISPs. When users click the shortened URL, it may take them to a fraudulent page which may contain malware.

You know that the URLs you are linking to are legitimate but beware – the extensive, global abuse of URL shorteners to send out spam has made them red flags for many ISPs. As a safeguard, add hyperlinks on keywords in copy or on images.

Stay away from using full URL links as text in the body of your email. Long URLs are not only ugly but they can also get your emails to be flagged as spam.

6. Host images in reliable websites

It’s a common practice for email marketers to use hosting services to host images and big files and link them to email. While it helps to decrease the message size and increase sending speed and loading time, ensure the image and link hosting service providers you choose are reliable and trustworthy.

There are many websites that provide free hosting services that may lead to a potential blacklist. The image hosting domain has a reputation and it should be safeguarded as the sending domain. 

Major ISPs like Gmail give fair importance to the image hosting path and the domain which is used in the link. Bad reputation of the image hosting path can lead to spam folder placement. 

Blacklisted image hosting domains can ruin inbox placements in B2B mailboxes. Majority of organisations have internet security systems which are mostly relied on blacklisting agencies. So blacklisting domains can really hamper the inbox placements in B2B mailboxes. 

7. Add alt text in images

Alt text (Alternative text) is a short description of an image that will be displayed. In this way, if the image gets blocked the user will be able to know what the image is. This usually happens to users who have blocked downloading images for a particular email client.

8. Maintain text-to-image ratio

Maintaining text to image ratio is a good practice for better user engagement. Emails that are purely image-based stand no chance with users who have  turned off the image-download option in their email settings. Knowing the audience and their preferences is key before deciding whether to use an image or text-based mailer.

There are situations where an image mailer performs better  than a text mailer. In some cases we recommend marketers to use image mailers for re-engaging inactive users. 

It’s recommended to maintain a minimum of 60 to 40 text-to-image ratio in email campaigns. There is a higher chance for heavy image-based emails landing in the spam folder. 

9. A/B testing

Email A/B testing is a way of determining email effectiveness in terms of open and click rate of two or more email creatives. 

In the test, two or more variations of a campaign are sent to a small percentage of the total subscribers. Half the recipients will be targeted with Version A and the rest, Version B. The winning version is determined by the higher open or click rates and it will be used to target the rest of the users.

A/B testing for email can be conducted based on variations in-subject line, email content, length of the mail, etc. Below is an example of an A/B test on email content.





Rome was not built in a day. Same goes for email deliverability and email inbox placement.

Successful email marketers advocate time-tested strategies, processes and practices for good email inbox placement rates.

Constant monitoring of user engagement and activity helps marketers gain insights into user needs and tailor content and communication accordingly.

As this article elaborates, email content management holds a big role in improving email deliverability. Follow the above email content management tips and fine tune your content, for greater success of your email campaigns.

As ISPs go on strengthening their email filtering algorithms, it’s up to marketers to stay on top of their email game – to fulfill the promises made to subscribers when they signed up! 


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