Ultimate Email Deliverability Guide: 25 Tips to Increase Engagement From Ricky Pearl

Created On
July 12, 2023
Ultimate Email Deliverability Guide

You're sending targeted cold emails with compelling messages to your target audiences, only to see rising bounce rate, poor deliverability, and low reply rates. This is not what should happen to your business. 

So, how can you avoid these issues and make sure your emails reach your prospects' primary inbox?

In this comprehensive guide, Ricky Pearl, the founder and CEO of Pointer Strategy, discusses the reasons behind poor deliverability and shares their best practices to maintain high email deliverability. They have also spilled some actionable strategies to enhance your email deliverability, sender reputation, ensuring that your messages land in your prospects' primary inbox. 

Let's dive right in.

Ultimate Email Deliverability Guide: 25 Tips to Slay Sales Outreach

Doing cold email outreach the right way is crucial for building effective connections and generating positive replies from prospects. A well-crafted and personalized cold email that caters to the recipient's needs, increases the chances of grabbing their attention, fostering meaningful conversations, and ultimately driving sales for your business.

Here are the 25 things you need to keep in mind for successful cold email outreach: 


DMARC (Domain-based Message Authentication), DKIM (Domain Keys Identified Mail), and SPF (Sender Policy framework) are email authentication methods. Together, they help prevent spammers, phishers, and other unauthorized parties from sending emails on behalf of a domain they do not own. Here's a breakdown:

  • DMARC: It helps prevent email spoofing and phishing attacks. It allows you to specify how email receivers should handle emails that claim to be from your domain. Implementing DMARC protects your domain's reputation, enhances email deliverability, and helps maintain the trust of your recipients.
  • DKIM: It establishes your email's authenticity, improves deliverability, and reduces the chances of your emails being marked as spam. DKIM verifies that the email content hasn't been tampered with during transit and confirms that it originated from your domain. 
  • SPF: It specifies which IP addresses are authorized to send emails on behalf of your domain. By configuring SPF records, you define the legitimate sources of your email traffic.

These authentication methods demonstrate that you take email security seriously and contribute to maintaining a positive sender reputation, which is crucial for successful cold email outreach.

2. Daily Email Sending Limits

Email sending limit largely depends on the age of the mailbox and sender reputation. For example-

Gmail: With a Gmail Standard account you can send 500 emails per day and 2,000 emails per day with a paid Google Workspace account.

Zoho: In the free edition, you can send 50 emails per user and add up to 3 users. In the paid editions, you can send 300 emails per user.

Outlook: You can send 300 emails maximum for verified Outlook.com email addresses per day.

If you suddenly start sending tons of emails, the ESP might flag your messages as spam and your emails might not even land in your prospects’ inboxes. To ensure your cold emails reach their intended recipients, it's recommended to send a moderate number of emails per day, usually no more than 50 per email account. By limiting your sending volume, you increase the chances of your emails being successfully delivered.

This indicates natural activity in your mailbox and increases email deliverability. Whether it's your first time sending cold emails or not, you should warm-up your email address to maintain natural sender activity and improve deliverability. 

3. Custom Domain Tracking

Custom tracking domain is a subdomain or an unique domain used to track email open rates and click-through rates. Custom domain tracking, instead of platform’s link tracking, helps improve sender reputation, email click-through rates, and email deliverability.  

Here are the benefits of using custom domain tracking: 

  • Custom domain tracking (branded tracking) creates a trusted impression to your prospects, which increases click-through rates. 
  • Branded domain tracking protects your domain from scammers, maintaining a high sender reputation. 
  • It overall improves deliverability and lowers the risk of landing in the spam folder or getting blocklisted. 

4. Avoid Sending Images in the First Email 

According to a Reply.io study, cold emails containing images and GIFs lowers reply rates by 12.7% and 25%. Images might take more time to load, losing your prospects’ interests entirely. Some ESPs block showing external images to their users, which can make the entire message irrelevant or uninteresting. 

This is why using images (and/or GIFs) is not a good idea, especially for the first email. Go for plain text emails, and if you really want, add images from 2nd or 3rd email. 

However, the data varies largely based on the industry you are catering to. So, before launching a campaign, test both plain text and image based variations to check which one works better for your audience. 

5. Be Careful of Spam Triggers

Your emails can get marked as spam due to many reasons, ranging from poor deliverability or misleading subject lines to using spam trigger words in your emails. 

Spam triggers are basically words or phrases that email service providers mark as fraudulent or malicious. Typically, these words or phrases over promise to the recipient in order to obtain important/sensitive information. 

Do not make fat claims, use salesy words, strangely formatted fonts, or all caps in your emails. Here’s a list of the most common spam trigger words you need to avoid: 

  • Earn $
  • No cost
  • Hidden
  • Passwords
  • Increase sales 

Check out the ultimate list of spam trigger words, here

6. Personalize Your Messages

Personalization is the key to your prospects’ hearts. Imagine receiving an email from an unknown sender with no regard to what you do or what you might look for. What will you do? You will delegate or move it spam. 

That’s where personalization comes in. In fact, companies typically see a 20% increase in revenue when their emails are personalized. Sending personalized cold emails can improve your deliverability and boost email open and reply rates. 

Let’s take a look at the ways you can personalize your emails: 

  • Mention where you found them (met at a webinar/read their blog post/seen interview) 
  • Complement them on their recent professional achievement
  • Mention company name/job role

You can use a sales engagement tool like Smartlead to personalize your outreach messages with custom personalization fields, such as first name of the prospect, company name, etc. 

7. Maintain Email List Hygiene

List hygiene is the process of removing invalid email addresses from your prospect list, also known as scrubbing. As per a Prospectify report, out of 1000 contacts, 45 contacts are no longer valid or in use after a month. 

Here are some email hygiene best practices: 

  • Do not buy contact lists from third-party providers (high risk of falling into spam traps) 
  • Removing invalid/fake email addresses regularly
  • Email list segmentation based on recipients’ preferences
  • Create suppression lists to maintain high sender reputation

8. Bounce Rates

Email bounce, in simple words, is a returned email that you sent. So, keeping an eye on the bounce rate is important to improve your deliverability and maintain sender reputation. Ideally, bounce rate should not exceed 2% of all emails sent. 

Here are some tips to help you reduce cold email bounce rates:

  • Use a reputable ESP: Choose a reliable ESP that has a good reputation for delivering emails and maintaining a low bounce rate, such as Mailchimp, Sendinblue, etc. 
  • Build a clean email list: Make sure your email list contains valid and relevant email addresses. Avoid purchasing email lists or scraping addresses from third-party scraping tools.
  • Verify email addresses: Before launching cold email campaigns, check the validity of the email addresses on your list. Use an email verification tool. 
  • Segment your email list: Categorize your email list based on factors such as industry, job title, or location. By segmenting your list, you can send more targeted and relevant emails to specific groups, increasing the chances of engagement and reducing the chances of bounces.
  • A/B Test and optimize your cold emails: Test different aspects of your cold emails, such as subject lines, email body, and call-to-action buttons. 
  • Implement proper email authentication: Configure SPF, DKIM, and DMARC records for your domain. 
  • Comply with email laws: Ensure that your cold email campaigns comply with email sending regulations – the CAN-SPAM act, GDPR,etc. 

9. Domain Limits

This is a no brainer. If you want to stay away from the spam folder, do NOT send more than 2 emails to the same domain in a single day. 

10. Slow Sending Speed

As we’ve already discussed, the ideal number of emails sent in a day is around 40-50 emails. However, this number is not scalable for businesses. But instead of pushing hundreds of emails from one account, diversify your outreach with multiple email addresses (with your domain name or subdomain) and reach out to a maximum number of prospects. 

Smartlead offers unlimited email addresses, so you can maintain a high deliverability & sender reputation. 

11. Randomize Email Sending Intervals and Numbers

Most bulk emailing tools or cold emailing tools offer sending intervals for campaigns. If you set a fixed interval for emails sent, ESPs might detect you as a spammer and blocklist your IP. That’s why it's better if you randomize the email sending intervals. 

This also goes for the number of emails sent from an inbox. If you send exactly 50 emails per day, it will draw attention to the spam filters. It’;s best you randomize the number of emails sent (40-50) from your sender account. 

12. Warmup Inboxes

Email warmup is the method of building sender reputation for a new sender account. To attain maximum email deliverability, it takes around 8-12 weeks of gradual warming up, or at the very least, a month. 

Start small with 2-3 emails a day and gradually increase the number of warmup emails sent each day till you attain maximum deliverability. 

13. Keep Warmup On

Now that we know the importance of email warmups, the next question follows. Should you keep warmup after launching a campaign? 

The answer is YES. Once you launch a campaign, boost the response rate to 80% and drop your warmups to 10 emails a day. Besides your campaign’s performance, this will increase and maintain a high sender reputation. 

14. Maintain Consistent Sending patterns

Go easy on your cold emails and the way you do it. Hurried activity in your email sending pattern can affect your deliverability. So, whether you are speeding up the number of emails sent, do it slowly. And the same goes for ramping down. 

15. Track DMARC and Blacklists

DMARC and blacklist monitoring provide all-in-all coverage for tracking email reputations. It ensures that your outbound messages are protected and helps maintain a positive sender reputation. By leveraging DMARC and blacklist monitoring, you can always maintain high deliverability and sender reputation. 

To keep it short, here’s how it helps: 

  • Blacklist monitoring safeguards your company's reputation
  • DMARC is crucial as it provides visibility into potential malicious email campaigns
  • The combination of blacklist monitoring and DMARC offers comprehensive insights 

16. Use Plain Text Emails 

While stylized HTML is the preferred option for email communication due to its popularity and numerous advantages, there are advantages to using plain text-style emails as well, especially for cold emails. 

Emails that use plain text or simpler HTML formatting are less likely to be flagged as spam by email clients. Some research suggests that plain text emails have a higher click-through rate. 

Moreover, plain text emails sound more natural. 

Additionally, plain text is compatible with wearable devices such as smartwatches and fitness trackers, which display messages in a text-only format. 

17. Limit Adding Links

The best practice is to not add links to your cold emails. But if it is absolutely necessary to send links, make sure to limit it to just one link (this includes your email signature). 

18. Pause Bad Campaigns

If your campaign is getting low reply rates consistently, just PAUSE it. Now, test your copy, tweak content, and test deliverability. Adjust warmup up replies and relaunch the campaign for a better performance.  

19. Strictly Follow the DND List

If you are reported as spam or a recipient has opted for ‘Do not contact’, it’s better if you don’t contact at all. Sending emails even after that not only risks your deliverability but also gives bad rep to your business. 

So, if someone opts out, make sure you remove them from your list. 

20. The Paradox of Unsubscribe Link

It’s funny: if you add an unsubscribe link to your emails, it will reduce your deliverability to some extent. On the other hand, it lowers the chances of getting marked as spam. 

Adding an unsubscribe link to your email helps in relationship building and keeping your email list clean. Moreover, including an unsubscribe link helps you comply with email regulations, such as the CAN-SPAM Act (in the United States) and similar laws in other regions.

21. Maintain a Low HTML-to-Text Ratio

While some minimal HTML elements like headers, bullet points, and properly formatted links can be beneficial, keeping the HTML to text ratio low in cold emails helps optimize deliverability, personalization, compatibility, and the clarity of your message.

A low HTML-to-text ratio can: 

  • Reduce the likelihood of being flagged as spam, increasing the chances of your cold email reaching the intended inbox.
  • Help you build a good connection with your prospects as you can send a personalized text based cold email. 
  • Increase device compatibility. 

22. Leverage SPINTAX

Spintax is a technique used to generate multiple variations of an email by replacing specific words or phrases with alternative options. Here's a basic guide on how to use spintax to spin your cold emails:

  • Determine the words or phrases in your email that you want to vary from subject line to CTAs. 
  • Wrap the alternative options within curly brackets { } and separate them with |. For example, if you want to spin a greeting, you could use {Hi|Hello|Hey}.
  • Use a tool such as Smartlead that supports spintax syntax to generate all possible combinations from your spintax content. 
  • Send the emails to a small test group within Smartlead to ensure they appear correctly in various email clients and devices.

23. Rotate Inboxes

If you are doing your cold email outreach from only one email account, please stop. Instead of using only one email address, create multiple to increase your sending limit. Keep 1-2 email addresses per domain and buy multiple domains or subdomains to create a bunch of sender accounts. 

Smartlead offers auto-rotation of the inbox to maintain high deliverability and sender reputation. You can add unlimited email accounts and send emails in rotation from each of the warmed-up sender accounts. 

23. Focus on Replies to Maximize Conversions

More than click-through rates, you should really focus on replies on your campaigns for maximum conversions. Make sure you reply to all the unsubscribed subscribers confirming that you won’t bother them. 

24. Add Value and Be Unique

Now that your email deliverability is top notch, what should you do? Write better emails, of course. 

An average email user receives around 120 emails a day, and it makes us wonder how many stand out from the bunch. Be smart on your targeting and the CTAs you are using based on your target audiences. So, don’t be afraid to be unique, write unique email copies and add value propositions. 

25. Relevancy Over Personalization

If you want meaningful engagement in your cold email campaigns, focus on the relevancy of your message for your prospect over personalization. It doesn’t mean that personalization is worthless, but it should come later. The first and foremost focus should be on the relevancy of the email and the value proposition it offers. 


Email deliverability operates in a continuous cycle, where increased engagement from your recipients leads to improved inbox placement. It is essential to monitor key email engagement metrics such as clicks, opens, and bounces to ensure that you are delivering relevant content to the appropriate recipients at the optimal times.

Thai is where a comprehensive sales engagement platform comes in handy. Smartlead offers unlimited unique IP servers and unlimited warmups to optimize deliverability. Smartlead enhances sender reputation with natural AI conversations and moves emails from spam folders to the primary inbox. It offers cold emailing API infrastructure. Custom-conditional email triggers and sub-sequences based on lead behavior can be set up. It provides a centralized master inbox, email tracking, and time-saving features like mailbox rotation and full whitelabel capabilities.

If you are intrigued by the amazing features Smartlead offers, start your free trial today.

If you are intrigued by the amazing features Smartlead offers, start your free trial today and if you want to learn more about B2B sales reach out to Ricky at Pointer Strategy.

Smartlead, get your email delivered and bring sales 

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What’s a Rich Text element?

The rich text element allows you to create and format headings, paragraphs, blockquotes, images, and video all in one place instead of having to add and format them individually. Just double-click and easily create content.

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  • svsv

Static and dynamic content editing

A rich text element can be used with static or dynamic content. For static content, just drop it into any page and begin editing. For dynamic content, add a rich text field to any collection and then connect a rich text element to that field in the settings panel. Voila!

How to customize formatting for each rich text

Headings, paragraphs, blockquotes, figures, images, and figure captions can all be styled after a class is added to the rich text element using the "When inside of" nested selector system.

Author’s Details

Sattwik Das

Sattwik is a Digital Marketing professional at Smartlead. He is a dedicated content writer who focuses on juggling words to bring out meaningful content. He is experienced in well-researched and SEO-optimized content creation, content editing, and copywriting for various businesses throughout the globe. His expertise in SEO, SMM, and SMO with a touch of creativity helps businesses grow and maximize their credibility and sales.


Edited by:

Charu Mitra Dubey


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