newsletter-subject-lines_skill

Overview

This skill writes high-open-rate subject lines for OpenEd Daily using 15 proven formulas plus a 10-Commandments evaluation. It generates 10+ distinct options, scores the top contenders with systematic criteria, and selects the best lines optimized for mobile previews. The goal is clear: increase opens with concise, memorable, and honest subject lines.

How this skill works

I identify the single core value or insight in the newsletter, match that insight to multiple subject-line patterns (Number + Why, Contrast, Curiosity Gap, Contrarian Truth, etc.), and produce 10+ candidate lines across 3–4 patterns. Then I score the top 5–7 options using the 10 Commandments and the 4 U's test (Useful, Urgent, Unique, Ultra-specific) and run final checks for length, clarity when truncated, and forwardability.

When to use it

• Preparing OpenEd Daily or education-focused email editions
• You need mobile-friendly subject lines (35–50 chars ideal)
• When you want data-backed, repeatable subject-line generation
• Before A/B testing newsletter subject candidates
• When headlines must balance curiosity with clarity

Best practices

• Start by naming the single most valuable insight; build the line around that
• Generate at least 10 options across 3–4 different patterns
• Prefer concrete numbers and specific claims over vague words
• Score top candidates with the 10 Commandments and the 4 U's test
• Keep lines clear if truncated; avoid hedging language
• Avoid clickbait, ALL CAPS, and emojis

Example use cases

• Daily edition highlighting one research finding: produce 10+ concise subject lines and pick the top 2 for A/B test
• Feature story about a school innovation: craft contrast and curiosity-gap lines, score them, and select best
• Subscriber growth campaign: create targeted subject lines naming the audience and a clear benefit
• Special report release: use Number + Why and Social Proof patterns to increase credibility
• Quick-breaking education policy update: emphasize urgency and the problem callout