One spam complaint per 1000 emails is the danger zone β above this, inbox placement drops sharply
Subject Lines
40-50 characters optimal β truncates on mobile after 35-40
Personalization works: name or company in subject increases opens 10-20%
Curiosity beats clarity for opens, but clarity wins for clicks β balance based on goal
Avoid spam triggers: ALL CAPS, excessive punctuation!!!, "free", "act now"
Test emoji: works for some audiences, hurts others β A/B test before committing
Preview text is second subject line β don't waste it with "View in browser"
Email Sequences
Welcome sequence (5-7 emails over 2 weeks):
1. Immediate: Deliver promised value + set expectations
2. Day 1: Best content or quick win
3. Day 3: Story/origin + values
4. Day 5: Social proof + case study
5. Day 7: Soft offer or deeper engagement
6. Day 10: Address common objection
7. Day 14: Clear CTA
First email in sequence has highest open rate β make it count
Space emails 1-3 days apart β daily is too aggressive for most audiences
Segmentation
Segment by behavior, not just demographics β what they clicked matters more than job title
Minimum viable segments: new subscribers, engaged (opened in 30 days), unengaged, customers
Tag on every click β builds behavioral profile automatically
Sunset unengaged subscribers after 90 days β send re-engagement, then remove
VIP segment for highest engagement β reward them with early access, exclusives
Timing and Frequency
Tuesday-Thursday mid-morning performs best on average β but test your audience
B2B: business hours. B2C: evenings and weekends can work
Frequency depends on value: daily works if valuable, weekly fails if boring
Let subscribers choose frequency β reduces unsubscribes significantly
Send time optimization: most ESPs offer this, use it
Campaign Types
Newsletter: regular value, builds relationship, low direct conversion
Promotional: clear offer, urgency, direct conversion focus
Transactional: receipts, confirmations β highest open rates, add value here
Re-engagement: "We miss you" + incentive + easy unsubscribe
Announcement: product launches, major updates β segment to interested only
Writing for Email
One goal per email β multiple CTAs dilute response
Write for skimmers: bold key phrases, short paragraphs, bullet points
P.S. lines get read β put secondary CTA or key point there
Plain text often outperforms HTML for personal-style emails
Mobile-first: 60%+ open on mobile β single column, large tap targets