7 Email Deliverability Do's and Don'ts That Actually Matter

How do I make sure my email gets to my subscriber's inbox?

It sounds like a simple question, but deliverability is more complicated than most marketers expect. A well-designed email with genuinely useful content counts for nothing if it lands in the junk folder. Good deliverability practice is what gets it to the inbox.

What is deliverability?

Email deliverability measures how consistently your campaigns reach your subscribers' inboxes without being flagged as spam or bouncing. Low engagement rates and high bounce rates are usually the first signs of a deliverability problem.

Some of the causes are obvious. Others are easy to miss. The good news is that most of them are fixable, and you can start from the moment someone new joins your list.

Don't use single opt-in lists

A single opt-in list adds subscribers immediately, with no confirmation step. That sounds convenient, but it leaves your list open to erroneous sign-ups, spam bots, and malicious entries. Bad data hurts your sender reputation over time.

Double opt-in lists require a confirmation email before the subscriber is added. The extra step filters out the noise from the start. Double opt-in lists tend to have higher engagement rates, and the subscribers on them are genuinely interested, which is exactly the signal ISPs want to see.

Do communicate regularly with your list

A permission-based list is a solid foundation, but it only stays healthy if you use it. Send a welcome email as soon as someone signs up, they are most likely to engage with you when you are already top of mind, and it sets the expectation that you will be in their inbox regularly.

After that, keep showing up. If subscribers go two or three months without hearing from you, they may forget they signed up at all. That leads to spam complaints, which damages your reputation with ISPs. You need to be a consistent, recognisable sender, not someone who appears once a quarter when you have a promotion to push.

Don't send from a free email address

Your from-address is one of the first things both subscribers and spam filters check. Sending from a Gmail, Hotmail, or Yahoo address signals to ISPs that you are not a legitimate bulk sender, and your campaign is likely to go straight to junk.

Send from an official company address at a domain you own, one that subscribers will recognise. We send from Hello@TouchBasePro.com, which makes it immediately clear who we are. Using a proper domain address also means ISPs can verify your identity, which builds your long-term sending reputation.

Do pay attention to your subject line

After the from-address, the subject line is the first thing both ISPs and subscribers see. Spam filters look for specific triggers: excessive punctuation (!!!), characters substituted with numbers or symbols ($P3C1AL CH4R@CT3R5), and subject lines written in ALL CAPS. Use these sparingly, and only when they genuinely fit your content.

More importantly, your subject line must accurately reflect what is inside the email. Adding "R.E." or "FWD" as a prefix to imply an existing conversation is misleading and will cost you trust, with both your subscribers and spam filters.

We have written about successful subject line formulas before if you want a practical starting point.

Don't use too many images

Early spammers used image-only emails to bypass text-based keyword filters. Spam filters adapted, and today a campaign with lots of images and very little text is still treated with suspicion by many filters.

There is a second problem too. Some email clients do not display images by default. If your campaign is mostly images and a subscriber cannot see them, the email makes no sense and they have no reason to click anything. Balance your text-to-image ratio so the email works even without images loading, and add alt-text to every image. This helps with spam filters and makes your campaigns accessible.

Do use full URLs

URL shorteners are a red flag for spam filters. Spammers use them to hide where links actually go, so filters treat shortened URLs with suspicion, even when the destination is completely legitimate. There is also no practical reason to shorten URLs in an email campaign. Unlike social media, there is no character limit.

Instead, wrap your full, valid URLs in clear call-to-action text. This drives higher click-through rates and gives ISPs a clean signal that your links are above board.

Don't send to uninterested subscribers

Low open and engagement rates tell ISPs that your recipients do not want to hear from you. That leads to lower deliverability, and eventually to outright blocking. The problem compounds: the more you send to unengaged subscribers, the more ISPs start blocking you, which pushes engagement rates down further across your next campaigns.

A re-engagement campaign is the most effective fix. Contact subscribers who have not opened anything in the past twelve months and ask them to confirm they still want to hear from you. Remind them what they signed up for and why your content is worth their attention. Give them a clear way to opt out if they are no longer interested.

Once the campaign is done, remove anyone who did not re-engage. Your list will be smaller, but the subscribers who remain are active and interested. Open rates go up, engagement rates go up, and ISPs start treating you as a trusted sender again.

---

A good deliverability rate is not a nice-to-have, it is the baseline requirement for any email programme to generate a return. Small adjustments to your list management and campaign setup make a real difference to whether your emails land in the inbox or disappear into junk.