Get exclusive CAP network offers from top brands

View CAP Offers

21 Tips for Improving Email Deliverability

Even though email marketing is adequate for any form of online promotion (which includes affiliate marketing), it’s important to remember that our efforts are always as effective as our email deliverability. Quite simply, if only 10% of the email list receives our communication then we’re effectively losing 90% of the possible profits. Here’s what to do to prevent this and get your email delivered:

1. Use a Good Email Service Provider (ESP)

These days, this is simply a must. The times when you could send an email on your own (from your own email outbox) are long gone. Try companies like AWeber or MailChimp.

2. Start With Double Opt-In

Although buying email lists is a fairly popular practice, we don’t advise you to simply include such addresses in your main list. Whenever possible, start with double opt-in as your main marketing vehicle.

3. Send From One Email Address

Even though it’s your ESP that sends the actual email, you still have to set the “from:” parameter. Always make sure to use the same email address for every communication. That way people can add it to their contact lists… Which brings us to:

4. Ask People To Add You To Their Contact Books

In your “welcome email” ask people to add your address to their contact books (to whitelist you). That way, your email will never end up in their spam folders.

5. Check Deliverability Manually

You can do this by including your own email addresses on the list, and then checking if the message has been delivered. To do this, you’ll need addresses on Gmail, Outlook, and other popular platforms.

6. Remove Bad Addresses

Whenever a given email address (subscriber’s) doesn’t exist, your ESP will let you know about it. You should remove such addresses right away. Lists that feature a lot of nonexistent addresses are most often spam lists, and this is how ISPs identify them.

7. Review Subscribers Reporting You As Spam

If someone has reported you as spam, say, three times in a row then you should probably remove them from your list manually.

8. Remove Inactive Subscribers

People who are not opening your emails are not very likely to convert on any of your offers…ever.

9. Segment Your List

After a while of doing email marketing, you will be able to segment your list and point out the subscribers who are responsive to most of your emails and those who are rarely active. Then, you can send some crucial communication only to the responsive group.

10. Send Text And HTML

This is about multi-part email that most ESPs allow you to send. Whenever doing this, make sure to send both parts of the MIME. Otherwise, you can be flagged by a heuristic filter.

11. Personalize Subject Lines

Whenever it’s possible (and makes sense), make sure to include your recipient’s name in the subject line. Most ESPs provide some shortcodes to make this straightforward.

12. Split Test Subject Lines

If your list is big enough to give you statistically significant results, you can split test two subject lines. As a result, you’ll get some good insights for future mailings.

13. Don’t Use All Caps


14. Don’t Use Spam-Heavy Words

Don’t use words and phrases like: free, guarantee, click here, dollar signs, “limited time offer” and so on. This goes both for the subject line and in the body of the message.

15. Don’t Use IP Addresses As Links

Spammers often present links as: If you do this, your email will be flagged as spam almost immediately.

16. Avoid Grammar Errors And Typos

Believe it or not, grammar is actually picked up by spam filters. If there are too many weird words in your email, it will be flagged. For example, a popular spam-word: “”

17. “You Have Received This Email Because”

It’s important to include this line of text somewhere in the footer. It makes your email seem more genuine to spam filters.

18. Add “Unsubscribe” Links

The presence of an unsubscribe link in the footer gives people a clear way of opting out, so they don’t have to report you as spam.

19. Contact Information In The Footer

If it’s possible, always provide genuine contact information. Include things like your business’ physical address, phone number, registered name and contact email. This will help you not to get flagged by spam filters.

20. Avoid Attachments

Attachments are one of spam discovery factors. Even though most of the time, attachments are perfectly okay in everyday communication, they can still get your email flagged. Don’t attach anything if you don’t have to.

21. Other Shady Elements

There are many other indicators that spam filters use to identify bad messages. Just to conclude this list, we can point out two: Java Script and embedded images. If you’re sending HTML messages then you might include some Java Script by accident, so make sure to be careful with it. When it comes to images, it’s a good idea not to use them at all, or include them through the interface provided by your ESP.