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Email Best Practices

Email marketing is a reliable way to nurture customers and share content, but success depends on strong deliverability. This guide explains how spam is detected, legal requirements, and best practices for improving your sending reputation.

Updated over 3 weeks ago

Prerequisites

Before getting started, ensure you have:

  • A verified sending domain

  • Proper opt-in consent from recipients

  • A compliant unsubscribe process in place

  • Clean and active email lists (no purchased lists)

  • Access to domain reputation tools (ex: Google Postmaster)

⚠️ Important: Failure to comply with spam laws can result in severe fines and blocked sending domains.


What is Spam and How is it Detected?

Spam refers to unsolicited bulk email, also known as UBE (Unsolicited Bulk Email).

Spam is detected through:

  • Spam filters, which scan emails against common criteria

  • Email firewalls, which can block your IP/domain entirely after repeated spam complaints

If your email is flagged often, providers may automatically send all future messages to Junk.


Spam Laws

Unintentional spam-like campaigns can harm your brand reputation and create legal risk.

Two major regulations include:

  • CAN-SPAM (United States)

  • CASL (Canada)


CAN-SPAM (United States)

CAN-SPAM stands for the Controlling the Assault of Non-Solicited Pornography And Marketing Act of 2003 and is enforced by the FTC.

Transactional emails are exempt, but marketing emails must comply.

Penalties

Non-compliance penalties can reach:

  • $43,792 per email violation

Multiple organizations involved in sending may all be held responsible.

How to Avoid Violating CAN-SPAM

Commercial emails must meet these 7 requirements:

  1. Keep header information accurate

  2. Use honest subject lines

  3. Clearly disclose the email is an advertisement

  4. Include a valid physical business address

  5. Provide a clear opt-out option

  6. Honor opt-outs within 10 business days

  7. Ensure any third-party tools you use are compliant


CASL (Canada)

Canada’s Anti-Spam Legislation (CASL) is one of the strictest anti-spam laws worldwide.

CASL requires opt-in consent before sending commercial messages.

Penalties

Violations can result in fines up to:

  • $1 million per violation (individuals)

  • $10 million per violation (corporations)

Victims may also sue if harm is proven.

How to Avoid Violating CASL

CASL requires:

  • Clear sender identification (name, address, contact info)

  • Consent records (express or implied)

  • Easy unsubscribe options

  • Opt-out honored within 10 business days

Express consent = direct opt-in
Implied consent = based on purchases or inquiries (expires after 6–24 months)


Spam Filters and How to Avoid Them

While filters vary, these best practices are widely accepted.


How to Improve Deliverability and Avoid Spam Filters

1. Boost IP Address Reputation and Sender Score

Mailbox providers assign a Sender Score based on your sending behavior.

If your IP is new, you should perform IP warming.

IP Warm-Up Plan

Weeks 1–2
Send only to subscribers active within the past 30 days

Weeks 3–4
Expand to subscribers active within the past 60 days

Weeks 5–6
Expand to subscribers active within the past 90 days

Consistency in volume and low complaint rates speeds up reputation building.


2. Maintain Strong Domain Reputation

Domain reputation reflects your history of engagement and trust.

What affects domain reputation?

  • Domain age

  • Website activity

  • Link quality

  • Content trustworthiness

How to check it:

Use tools like Google Postmaster for Low–High reputation scoring.

How to improve it:

  • Use authentication protocols

  • Send from a dedicated subdomain

  • Maintain balanced sending frequency


3. Keep Bounce Rates Low

Hard bounces reduce sender reputation.

Best practice: Regularly clean your email lists and use bulk email verification tools.


4. Ensure Metadata is Accurate

Metadata includes:

  • From

  • To

  • Date

  • Subject

AIQ recommends personalizing recipient fields using macros instead of raw email addresses.

Misleading subject lines or sender info can violate both CAN-SPAM and CASL.


5. Remove Excess Code

Messy HTML (broken tags, incomplete formatting) increases spam risk.

Keep templates clean, simple, and validated.


6. Tailor Content to Boost Engagement

Segmentation improves engagement.

Studies show:

  • 72% of consumers prefer personalized messaging over generic emails.

Send content based on customer preferences and behavior.


7. Provide High-Quality Email Content

Avoid spam triggers by focusing on:

  • Descriptive link text (no naked URLs)

  • Working links

  • Balanced image-to-text ratio

  • Mobile-friendly design

  • Correct spelling and grammar

  • Avoiding spam trigger words (“Act now!”, “100% free”, etc.)


8. Properly Format Emails

Avoid formatting that looks spammy:

  • ALL CAPS

  • Multiple exclamation points

  • Too many colors

  • Too many fonts or sizes


Image Recommendations

Before uploading images to AIQ, follow these guidelines:

Format

Use PNG, JPG, GIF, or WEBP.

Alt Text

Always add alt text for accessibility and download issues.

High-Definition Screens

Use higher resolution images to avoid fuzziness on retina displays.

Color Mode

Save images in RGB, not CMYK.

Image Size

  • Recommended max file size: 1MB

  • Email template width: 600px


Image Width Guidelines

Content Type

Max Width

Full-width section image

564px

2-column images

264px

3-column images

164px

Padding defaults to 10px but can be removed for edge-to-edge images.


Troubleshooting

Issue: Emails landing in Spam
Solution: Improve sender reputation, reduce bounce rate, verify domain


Issue: High unsubscribe or complaint rate
Solution: Segment lists and send more relevant content


Issue: Domain blocked by firewall
Solution: Review sending practices and remove low-quality lists immediately


FAQ

Do I need consent to send marketing emails?


Yes — CASL requires opt-in consent, and CAN-SPAM requires opt-out compliance.


How long does IP warming take?


Typically 4–8 weeks, depending on engagement and complaint rates.

Need Help?

If you need assistance, reach out to AIQ Support anytime via the chat widget within your AIQ Dashboard.

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