How to Boost Deliverability and Win at Email Marketing Your email list can and should be the most reliable and cost-effective user acquisition tool. Take advantage of these tips to make sure that is true for your business.

In my last piece for Entrepreneur.com, I went over the basics of email deliverability -- what it is, the key metrics to understand and some of the tools to use to understand how your deliverability is being scored by the major inbox providers. Hopefully, you have adopted the use of some of those tools and have fairly good insight into your deliverability rating. Now that you understand your goals for deliverability and how to measure the effectiveness of any of your efforts it is time to get into the actual tactics and actions you can take to improve your inbox placement.

Related: 5 Ways Email Marketing Can Help Boost Ranking In a Hurry

The basics of list maintenance

There are hundreds of actions that may have an adverse impact on your deliverability -- particularly when you are accelerating your list growth through using tools like ReferralCandy to build incentive-based referral programs or DojoMojo to run giveaways and sweepstakes (full disclosure: I am a founder of DojoMojo), which are powerful growth engines but can also result in the acquisition of many less-qualified emails that require active maintenance.

Fortunately there are numerous methods you can adopt to improve your reputation. The key is to identify which of these efforts are likely to have the highest return on investment in the form of making sure that your emails get in front of your target audience. When confronted with our own list issues, these were some of the actions -- among the nearly countless ones we tried -- that yielded the highest return for us.

Prune your list regularly.

Think of your email list as a garden that requires constant nurturing. While many delicious fruits and vegetables may grow therein, weeds will also spring up from time to time. Left untended, the weeds will overrun your garden and ravage your otherwise healthy plants. But, if you actively prune those weeds so your vegetables and fruits have space and can grow, your garden will become more vibrant than ever.

Related: How Email Marketing Can Help Build Your Brand

In much the same way with email, you need to be diligent about removing unengaged users from your list. I hear all too often that brands are reluctant to remove users from their list in the vain hope that they will someday become engaged. Trust me: If someone has not opened an email from you in six months, he likely never will. Not only are you paying your email service provider (ESP) to have that person in your list but you are harming your ability to reach your already engaged existing audience. Worse yet, any future emails you acquire will as a result be even less likely to see your communications. Since success is defined as having an engaged email list, and not simply a massive one, it's important to be proactive about ridding your list of unengaged users regularly.

Make it incredibly easy for a user to unsubscribe.

This should go without saying but bears repeating. Ensure that each message you send includes a working unsubscribe within the email. Some ESPs like Mailchimp automatically generate these links and include them in the footer of each email, while others like Sendgrid do not. If you're using an ESP that doesn't include the link by default, be sure you add one in yourself, and make sure that it's simple and easy-to-see. You never want to thwart people who want to unsubscribe from your list by complicating the process, which is unsurprisingly one of the fastest ways to get into hot water with the inbox providers.

Don't include the words "click here" in an email.

"Click here" is a phrase that can often trigger spam filters. In fact, many unsubscribe links read as "Click here to unsubscribe from messages like this," which somewhat ironically can cause spam triggers. Be sure to use copy in unsubscribe links that avoids the spam-triggering terminology and utilizes alternate phrases and action words.

Related: How to Make Sure Your Company's Emails Stay Out of the Spam Folder

Make sure all images have an alt tag.

Alt tags allow the inbox providers to read images. Many senders will leave the alt tags blank, but that ultimately translates as an empty space to the inbox provider, prompting your message to end up in the spam folder since the content appears to be blank. Always add alt tags to each image that give a brief description of what the image is displaying. This not only allows the inbox providers to better understand what you are sending, but also displays this text if the images are unable to render properly in the user's inbox.

Perform list hygiene and verification.

There are a number of third-party services that, for a fee, will run emails through verification and hygiene filters to ensure that an email is both real and unassociated with any known spam traps, blacklists or other risky domains. While this method differs from the others on this list in that it comes with a monetary cost, using a third-party software can be incredibly powerful particularly in cases where your reputation is already damaged. There are a number of good providers to evaluate including companies like Webbula and BriteVerify.

Focus on communicating with engaged users.

While you may not want to immediately remove users who have not engaged with your last several emails from your list in the hopes that you can re-engage them in the near future, you should be careful not to target them in your communication, either. Instead, focus on messaging your engaged base to ensure your deliverability metrics remain well above industry averages. This of course signals to the inbox providers that you are a good sender, which will gradually improve your deliverability ratings. Then, when you are ready with a specific re-engagement campaign for dormant users still in your list, you can prepare very specific content with them in mind.

Related: 6 Keys to Email Marketing Success

Low-hanging engineering fruit

There are quite a few best practices worth undertaking here, but as almost every business owner will attest, engineering hours are among the most precious resources. With that in mind, here are the most impactful initiatives that require the least amount of effort. Fortunately, most of these require a single set up and relatively little maintenance.

Email signing with Google apps. This ensures that your emails are electronically signed to legitimize emails in a way that can be verified by recipients using a public-key. A short overview of how to undertake this process can be found here.

Set up Sender Policy Framework (SPF). SPF configuration ensures that spammers cannot send from your domain.

Set up DomainKeys Identified Mail (DKIM). DKIM allows an organization, as the handler of the message, to take responsibility for its message. Having DKIM set up validates the domain's identity through cryptographic authentication.

Related: Hitting the Marketing Email Sweet Spot With Millennials (Infographic)

Domain-based Message Authentication, Reporting & Conformance (DMARC). DMARC aims to create a collaborative system fo senders and receivers to improve mail authentication practices and reject unauthenticated messages. The process for registering your domain with DMARC is fairly straightforward and easy.

Ensure that WHOIS information is up to date. WHOIS information identifies your domain as the sender. This is where you're able to assign a name and address to your domain through your hosting service (for instance a provider like Amazon Web Services). Even if this was already set up, you'll want to double check and make sure that the information isn't outdated.

Deliverability is hardly something that can be improved overnight, especially if you've already damaged your reputation. By following these steps and staying disciplined in your sending practices and principles, however, it is possible to see positive changes in both your open and click-through rates after experiencing even the most drastic slip. The secret is to be as patient as you are diligent and proactive, and to give your efforts time to result in stronger deliverability, more engagement and, in the end, successful conversions. Your email list can and should be the most reliable and cost-effective user acquisition tool in your repertoire, so take advantage of these tips to make sure that that remains true for your business.

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