Email Deliverability Tips That Actually Move the Needle

Email deliverability tips are the difference between “we sent a campaign” and “people actually saw it.” If your opens crater, your best copy won’t save you—because Gmail, Outlook, and Yahoo are judging your sending behavior long before a human does.

Below are the practices I’ve seen consistently improve inbox placement in real-world email marketing programs (not just theory, not just “warm up your domain” one-liners).

1) Authenticate like you mean it (SPF, DKIM, DMARC)

Mailbox providers increasingly treat authentication as table stakes. If you’re not properly set up, you’re asking to be filtered, throttled, or spoofed.

Minimum bar:

• SPF: Authorize your ESP and any other senders (transactional providers, CRMs).
• DKIM: Sign outgoing mail so it can’t be tampered with and can be attributed to your domain.
• DMARC: Tell receivers what to do when SPF/DKIM fail—and get visibility.

Opinionated take: DMARC without enforcement is a half-measure. Start at p=none to monitor, but move toward quarantine/reject once you’ve confirmed all legitimate senders.

Actionable example: a basic DMARC record you can publish (adjust addresses and policy):

_dmarc.yourdomain.com TXT "v=DMARC1; p=quarantine; rua=mailto:[e-mail]; ruf=mailto:[e-mail]; fo=1; adkim=s; aspf=s"

Why this matters for deliverability: authentication + alignment is a strong trust signal. It also reduces the chance that someone else burns your domain reputation with spoofed mail.

2) Protect your domain reputation (and stop “list growth” from poisoning it)

Your reputation is an aggregate score of how receivers experience your mail. Once it’s damaged, you’ll feel it across campaigns—even the “good” ones.

Key habits that keep reputation healthy:

• Use double opt-in for new lists (or at least confirmed opt-in for higher-risk channels). Yes, growth slows. Deliverability improves.
• Never import cold lists into marketing sends. If you must contact them, do it as a separate re-permission flow and be prepared to lose most of them.
• Segment by engagement: send more to people who open/click; throttle or sunset chronically unengaged users.
• Set a clear cadence. Sporadic bursts look like spammer behavior (especially after months of silence).

A practical rule: if a subscriber hasn’t opened in 90–180 days, stop mailing them automatically. Create a win-back, then suppress.

3) Make engagement easy (because inbox placement follows behavior)

Modern filtering is brutally behavior-driven. If recipients ignore you, you’ll gradually be routed to Promotions, bulk tabs, or spam.

Do these and you’ll usually see better placement:

• Write subject lines that match the body. “Curiosity” that leads to generic content trains people to ignore you.
• Keep the first 100 pixels clean. Your preheader should reinforce the value, not show “view in browser” and legal text.
• Ask for a reply occasionally. Replies are a strong positive signal. Use it naturally: “Hit reply with your #1 question.”
• Use plain-text style for some campaigns. Not always, not for every brand—but mixing formats can increase real reading behavior.

Deliverability reality check: there’s no magic “spam words” blacklist that matters more than engagement, complaints, and authentication. If your audience wants your emails, you can get away with a lot.

4) List hygiene and complaint management (the unsexy multiplier)

If you want consistent inboxing, treat hygiene like engineering, not a one-time cleanup.

Non-negotiables:

• Honor unsubscribes instantly. Delays create complaints.
• Remove hard bounces automatically (your ESP should do this).
• Watch spam complaint rate like a hawk. If it spikes, stop and investigate—don’t “push through.”
• Use a dedicated sending domain (e.g., mail.yourdomain.com) to isolate marketing from core corporate mail.

When things go wrong, debug in this order:

1. Did we change audience source (new lead magnet, partner list, giveaway)?
2. Did we change volume/cadence suddenly?
3. Did we change content/template (new link patterns, heavy images, tracking changes)?
4. Did authentication break (DNS edits, new provider, expired DKIM)?

5) Tools and ESP choices (soft mention)

Most deliverability issues aren’t caused by your ESP, but your ESP can make best practices easier—or easier to mess up.

A few notes from the field:

• Mailchimp is fine for straightforward newsletter programs, but teams often outgrow its segmentation and lifecycle automation unless they’re disciplined.
• ActiveCampaign tends to shine when you’re serious about behavioral automation and granular segments (which can improve engagement—and therefore deliverability).
• Brevo (formerly Sendinblue) can be a pragmatic choice for multi-channel marketing on a budget, but you still need to do the hard parts: authentication, hygiene, and cadence.

My take: pick a platform that makes it simple to suppress unengaged users, track complaints/bounces, and separate transactional vs marketing streams. Deliverability is mostly process—your tool should support that process instead of encouraging “blast everyone.”