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Email Best Practices
📤 The Complete Guide to Email Deliverability
A comprehensive, practical template to help improve and maintain inbox placement for marketing, sales, and transactional emails.
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📬 But Sara….What Is Email Sending Reputation?
Email sending reputation is a score that mailbox providers (like Gmail, Outlook, Yahoo, etc.) assign to your IP address and domain based on how recipients interact with your emails. A strong reputation increases your chances of landing in the inbox; a poor one can send your emails straight to spam…or block them entirely.
💡 Best Practices to Maintain a Good Sending Reputation
Table 4
Area
Best Practice
Area
Best Practice
Authentication
Set up SPF, DKIM, and DMARC for your domain
Consistent Volume
Avoid large spikes in email volume — warm up gradually
Engagement Monitoring
Regularly monitor opens, clicks, bounces, and spam complaints
List Hygiene
Clean your list frequently and remove inactive or bounced emails
Opt-In Practices
Use double opt-in and never buy or scrape email lists
Avoid Spam Triggers
Watch subject lines, avoid all caps, misleading language, or image-only emails
Feedback Loops
Set up complaint feedback loops with providers like Yahoo and Microsoft
There are no rows in this table
SECTION 1: DOMAIN AUTHENTICATION & COMPLIANCE
Proper domain authentication is non-negotiable for inbox placement. If you don’t have these set up, you risk being sent straight into the spam folder.
The way I like to explain this to clients: this is like running up to someone in a cafe and asking them to send your invitations to all of their friends. If you run up without introducing yourself, you’ll likely scare the person and they’ll throw most of your invites in the trash; if you introduce yourself, show ID, and build credibility, your invitations are more likely to send up being sent properly. It’s all about seeing a good first impression!
Table 5
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
SPF
Tells receiving servers which senders are allowed to send on your behalf
Add a TXT record in your DNS zone
DKIM
Adds a digital signature proving the message was authorized and unmodified
Set up in your ESP and publish DNS record
DMARC
Aligns SPF & DKIM and tells mailbox providers what to do with unauthenticated mail
Start with p=none and monitor reports
BIMI
Enables logo display in inboxes (ex. Gmail, Yahoo)
Requires DMARC + VMC Certificate
There are no rows in this table
SECTION 2: INFRASTRUCTURE & SENDING STRATEGY
These are foundational elements to separate your good messages from spammy traffic.
If you want to work to ensure you have great inbox placement, look here to set further foundation.
Table 6
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
There are no rows in this table
SECTION 3: LIST QUALITY & SENDER REPUTATION
This is where most issues originate. Poor list hygiene = poor inboxing.
It’s not enough to set the foundation — your email sender reputation is something that has to be taken care of and tracked, month over month.
Table 7
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Double Opt-In
Verifies intent and reduces bounces
Configure in ESP
Typically available in most email service providers
Clean Lists Regularly
Removes bounces, traps, inactives
Clean quarterly or monthly
Suppress Unengaged
Reduces risk of spam placement
No opens/clicks in 90+ days
Use ESP segmentation
Example of unengaged suppression in HubSpot:
Monitor Complaints & Bounces
High rates damage sender score
Review post-send dashboards
There are no rows in this table
SECTION 4: EMAIL CONTENT & DESIGN
Good content doesn’t just look good, it also impacts inboxing.
If you do all of the things above but are sending junky content, you’ll end up in the Promotions or Spam folder.
Table 8
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Avoid Spammy Subject Lines
Prevents spam triggers
Avoid ALL CAPS, misleading text
Many ESPs have this within their preview functionality
Alt Text & Mobile Optimization
Improves accessibility
Use responsive HTML; avoid image-only
Plain-Text Version
Boosts inbox placement
Auto-generated, but review manually
Test Before Sending
Detect spam, render issues
Send to seed list or spam checker
There are no rows in this table
SECTION 5: MONITORING & ONGOING OPTIMIZATION
Inbox placement is a moving target. These tools help you stay ahead.
BTW: Gmail and the other ESPs continue to make updates, email is not something you just “set and forget.” These tools and practices will help you stay on top of the latest.
Table 9
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Item
Why It Matters
How to Check / Fix
Tools
Educational Resources
Inbox Placement Testing
Know where your email lands
Test monthly or pre-campaign
There are no rows in this table
🧪 BONUS: WARM-UP PLAN FOR NEW DOMAINS/IPs*
*This also applies if you’re moving domains or migrating tools!
Week 1: Send to 100–500 highly engaged, ideally validated email address contacts/day
Week 2: Scale to 1,000–2,000/day, mixing in newer segments
Week 3+: Double volume weekly until fully ramped
Pro Tip: Start with engagement-based segments to build trust.
📈 Email Warm-Up Schedule
Remember, this is not only for when you first start a new email program — this also applies for any major changes, like marketing automation or sales automation platform migration.
Table 10
Week
Daily Volume
Audience Description
Notes
Week
Daily Volume
Audience Description
Notes
Week 1
100–500/day
Highly engaged, validated email addresses
Use only contacts with high open/click rates
Week 2
1,000–2,000/day
Mix of engaged + newer segments
Begin slowly expanding to colder but opted-in leads
Week 3
2,000–4,000/day
Expand to broader active list
Continue to monitor engagement + bounce rates
Week 4
4,000–8,000/day
Include newer leads and larger segments
Gradually introduce less-tested segments
Week 5
8,000–16,000/day
Most of your email list
Monitor domain/IP reputation closely
Week 6+
Full list (based on cap)
Entire subscriber base
Full sending volume if reputation is stable
There are no rows in this table
☑️ Email Deployment Checklist
Copy + paste this and add in your own unique steps for your business!
Table 11
Category
Item
Description
Owner
Status
Notes
Category
Item
Description
Owner
Status
Notes
Strategy
Audience Segment Confirmed
Correct list or segment selected
☐
Send Goal Confirmed
Promotional, nurture, transactional, etc.
☐
Suppression Lists Applied
Exclude unsubscribed, unengaged, internal, or recent recipients
☐
Content
Subject Line Finalized
Clear, non-spammy, on-brand
☐
Preview Text Finalized
Complements subject line, entices opens
☐
Body Content Proofed
No typos, consistent tone, brand voice
☐
CTA Buttons/Links Added
All call-to-action buttons work
☐
Personalization Tokens Validated
First name, company name, etc. inserted correctly
☐
Design
Responsive Design Tested
Mobile and desktop rendering confirmed
☐
Images Properly Sized & Hosted
ALT text included, no broken links
☐
Plain Text Version Reviewed
Not auto-generated gibberish
☐
Accessibility Considered
Contrast, font size, screen-reader compatibility
☐
Testing
Inbox Rendering Previewed
Litmus, Email on Acid, or ESP previews
☐
Spam Score Checked
Passed through Mail Tester or similar
☐
All Links Tested
UTM tags applied and working
☐
Send to Seed List
Internal QA before full deployment
☐
Technical
Sender Name & Email Correct
Matches brand + complies with SPF/DKIM/DMARC
☐
From Address Verified
Registered with ESP, SPF aligned
☐
Unsubscribe Link Working
Clearly visible and functional
☐
Footer Info Compliant
Includes company address, privacy policy, etc.
☐
Deployment
Send Date/Time Finalized
Consider time zone, send caps, and frequency
☐
Final Approval Received
All stakeholders signed off
☐
Campaign Scheduled/Sent
Confirm send happened successfully
☐
Post-Send Monitoring
Check for bounces, complaints, and early performance
☐
There are no rows in this table
📄 Helpful Additional Cheat Sheets
List of all freemium email domains:
List of email malformations I typically filter for:
Table 12
Issue Type
Examples
How to Filter/Flag
Issue Type
Examples
How to Filter/Flag
Missing "@" symbol
john.doe.com, johndoeemail.com
NOT CONTAINS "@"
Missing "." after "@"
john@doecom, hello@domain
NOT CONTAINS "." AFTER "@"
Starts or ends with special characters
.john@doe.com, john@doe.com.
STARTSWITH(".") OR ENDSWITH(".")
Consecutive dots
john..doe@example.com
CONTAINS ".."
Too short
a@b.c
Length check: LENGTH < 6
No domain portion
john@ or john@.
NOT CONTAINS "." after @
No local part (before @)
@example.com
STARTSWITH("@")
Nonsense strings or keyboard mashing
asdfasdf@asdf.com, qwe@qwe.qwe
Regex match for repeated characters or gibberish
Temporary/throwaway domains
test@mailinator.com, abc@tempmail.com
Filter by known temp domains (see below)
Obvious fake terms
test@domain.com, fake@email.com
CONTAINS "test" OR "fake"
Non-alphanumeric characters in domain
john@doe!.com
Regex for special characters in domain
Spaces in email
john doe@example.com
CONTAINS " "
Emails ending in numbers suspiciously
test123456789@domain.com
Regex for numeric endings
Multiple "@" symbols
john@@example.com
Count "@" > 1
HTML tags or JS
<script>@email.com
CONTAINS "<" OR ">" OR "script"
Test emails
Starts with test@ (or you can experiment with contains, just be aware that some legitimate names look this way on corporate email, like Tim Estes could be )
There are no rows in this table
Typical throwaway email domains:
✍️ Enterprise Pro Tips
— seriously. Full transparency, I am an ambassador, but that’s because I really love their tool and used it in the Enterprise world — it saves you SO MUCH TIME in Enterprise campaign ops, especially if you have a centralized email/LP creation and deployment group but not the appropriate staffing to support your stakeholders.(Did you find this helpful? Sign up for more MOPS content from Sara here: )
P.S. One thing I didn’t include in here is email consent compliance — this varies depending upon where your business is and where your prospects are. LMK if you want another guide about that, but it felt like too much to include in here. 😅
🗣️ Have feedback? This is a public resource for us all to use — please email me at if you have any feedback or ways I can improve upon this!
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