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Improve Gmail subject lines in mail merge campaigns

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Subject lines decide whether your email gets opened. Even small changes can make a measurable difference.

What good subject lines have in common

  • Clear context
  • Natural wording
  • Short length
  • Relevant personalization

Ready-to-use subject formulas

  • “{{FirstName}}, quick question about {{Topic}}”
  • “Idea for {{Company}}”
  • “Following up on {{Topic}}”
  • “Can I share a short example?”

Common mistakes

  • Too many symbols or all caps
  • Overly promotional language
  • Subject lines that are too long on mobile
  • No relevance to recipient context

Quick A/B process

Split your list into two equal groups and test two subject lines. Keep the winner for your next batches.

Conclusion

Better subject lines are one of the fastest ways to improve campaign performance. Test often and keep what works.

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