Best Practices for Cold Email in 2025

Cold email is legal when done right. Violate regulations and you face fines, blacklisting, and damaged reputation. Know the rules.

CAN-SPAM (US) requirements:

• Accurate "From" name and email address
• Truthful subject lines (no bait-and-switch)
• Clear identification as an advertisement (if applicable)
• Physical mailing address in the email
• Working unsubscribe mechanism
• Honor unsubscribe requests within 10 business days

GDPR (EU) considerations:

• Legitimate interest basis for B2B outreach
• Relevance to recipient's professional role
• Easy opt-out mechanism
• No persistent contact after objection

Your results are only as good as your list. A small, targeted list beats a massive, generic list every time.

List building best practices:

• Verify emails before sending (use verification tools)
• Target by role, not just company
• Prioritize decision-makers over influencers
• Update lists quarterly (people change jobs)
• Remove bounced emails immediately
• Segment by industry, company size, or pain point

Never send cold email from your primary domain. One spam complaint can tank your entire company's email deliverability. Use dedicated sending domains.

Domain setup checklist:

• Register a variation of your domain (tryyourcompany.com, getyourcompany.com)
• Set up SPF record to authorize sending servers
• Configure DKIM for email authentication
• Add DMARC policy for protection
• Set up custom tracking domain

Warmup schedule:

1. Week 1: 5-10 emails/day
2. Week 2: 15-25 emails/day
3. Week 3: 30-50 emails/day
4. Week 4: 50-100 emails/day
5. Ongoing: Increase by 10-20% weekly

The subject line is your foot in the door. Mess it up and the rest of your email doesn't matter.

Subject line do's:

• Keep it under 50 characters (mobile-optimized)
• Personalize with first name or company
• Use questions to spark curiosity
• Test lowercase for casual tone
• Create urgency without clickbait

Subject line don'ts:

• ❌ ALL CAPS (spam trigger)
• ❌ Excessive punctuation (!!! ???)
• ❌ Spam words: Free, Guaranteed, Act Now, Limited Time
• ❌ Misleading or clickbait subjects
• ❌ Re: or Fwd: (unless true, it's deceptive)

"Quick question, {{first_name}}" - 28% open rate
"{{company}} + {{your_company}}" - 32% open rate
"Idea for {{company}}" - 26% open rate
"Are you using {{competitor}}?" - 24% open rate
"hi {{first_name}}" - 22% open rate (lowercase test)

Great cold email copy feels like a message from a colleague, not a broadcast from a company. Here's how to nail the tone.

Copy best practices:

• Length: 50-125 words maximum
• Paragraphs: 1-2 sentences each
• Tone: Casual, conversational, helpful
• Focus: Their problems, not your features
• CTA: One clear, low-friction ask

Subject: Quick question, {{first_name}}

{{first_name}}, saw {{company}} just raised Series B—congrats!

With that kind of growth, you're probably thinking about 
scaling outreach without losing the personal touch.

We've helped 3 similar companies automate while keeping 
reply rates above 25%.

Worth a quick chat?

[Signature with social proof]

80% of sales require 5+ follow-ups, but 44% of reps give up after one attempt. Persistence pays—but there's an art to it.

Follow-up best practices:

• Send 3-5 follow-ups over 2-4 weeks
• Add value with each touch (don't just "bump")
• Vary the angle—new info, social proof, different CTA
• Space them 2-5 days apart initially
• Send the breakup email last

Follow-up value additions:

• Share a relevant article or case study
• Reference new company news
• Offer a different format (video vs. call)
• Provide a useful tool or template

What works for one audience bombs with another. Test everything and let data guide your decisions.

Testing priorities (in order):

1. Subject lines - Biggest impact on opens
2. Opening lines - Biggest impact on reads
3. CTAs - Biggest impact on replies
4. Send times - 10-15% improvement possible
5. Email length - Test short vs. medium

Going from 50 to 5,000 emails a day requires more than a bigger "send" button. Scale wrong and you'll destroy your domain reputation.

Safe scaling checklist:

• Test at small volume first (prove the offer)
• Increase volume 10-20% weekly
• Monitor deliverability metrics daily
• Use multiple sending domains if needed
• Maintain list quality as you scale
• Don't sacrifice personalization for volume