The Do’s and Don’ts of Subject Lines

The Do's and Don'ts of Subject Lines

These days email is a primary form of communication but your subscribers will more than likely receive tens if not hundreds of emails a day. So how do you make your subject line stand out from the rest?

There’s a lot of hype around creating the ‘perfect subject line’, but it still seems that no-one has ever found any concrete evidence of what works and what doesn’t. Here at Inbox Insight we take pride in delivering engaging campaigns for our clients and our subscribers so creating informative subject lines is a daily battle. Here is a glimpse of what we’ve picked up along the way…


  • Keep it short and sweet – Litmus discuss in depth about subject line lengths and their corresponding open and click rates.
  • Know your audience – don’t send out irrelevant content.
  • Be original – repeating the same content to your subscribers will result in unsubscribes.
  • Use a recognisable sender address.
  • Check and re-check for spelling mistakes.


  • Be misleading – people don’t want to open an email and read content that is vastly different to the subject line.
  • Use Symbols and Characters.
  • “Don’t sell what’s inside. Tell what’s inside” – Research from MailChimp showed that open rates are lower if the message appears to be ‘salesy’.
  • Don’t use the word ‘free’ too … well, freely! If something is free, then say so but don’t be misleading.
  • Shout about it – using capital letters will create an ENTIRELY DIFFERENT MESSAGE. Get it? Good.
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