When subject lines go bad

So the responsive email template design looks awesome and the lists you’re going to use are in tip-top shape.

All that’s needed now before pressing send is to come up with a sharp subject line; and that’s the easy part right?

‘Easy’ is nowhere even near to being true when it comes to subject lines and if we’re completely honest I think we’d all say we struggle when it comes to this part of producing email campaigns.

There’s probably no such thing as the perfect subject line but to help relieve some pressure what you could do is forget about blindly focusing on increasing response rates, go back to the start, and think about what you want your subject line to acheive.

A good starting point

Failed attempts at humour and mysterious statements that attempt to generate intrigue are just two approaches that will more than likely result in people deleting an email based on the subject line alone.

You’ll find it helpful to come up with your own reference list and here’s a few suggestions  that should help keep your writing of subject lines on track:

  • Keep it short and be descriptive
    20 to 30 characters is fine and remember that on mobile devices space is limited. You don’t need to create a mini version of the email on the subject line.
  • Make it personal
    There’s nearly always scope for personalisation and you don’t need to stop at ‘Hi Adi, blah…’ – be creative and use any relevant list data that could improve your subject lines.
  • Don’t make it sound super-mega-awesome
    ‘Last chance’, ‘Final offer’, ‘Too good to be missed’… errr, no – don’t do that. Us Brits are more cynical than most but I don’t think that approach works on anyone.
  • Don’t attempt to trick people
    Pretending this is a reply or forwarded message by adding ‘RE:’ or ‘FW:’ to the start of a subject line is really very sad.
  • Don’t try to confuse people
    ‘The GTX 151 now has a 3mm turbo rotor flex gangel pin for better control’ – I have no idea what that means.
  • Use common sense
    The word ‘Free’ isn’t an instant nuke but in combination with some other choice words it’s never going to come across well.
  • Use more common sense
    Don’t use ALL CAPITAL LETTERS (unless there’s a very good reason to) and keep exclamation marks under control!!!
  • Read what you’ve written out loud
    You receive stacks of emails every day so you’ll already know what sounds terrible and will make you want to delete or opt-out of receiving any further emails.

A few tips

Testing is the key really and it’s worth taking extra time to become aware of any issues before pressing send.

  • Placeholders
    Always remember to add the real subject line. It might not be ready whilst the template is being designed but the last thing you want is to end up with ‘no subject’ or ‘subject TBC’.
  • Personalisation
    A missing first name can lead to an ugly subject line. Use some template language to put a conditional statement around personalisation and to not only save time messing with data but to also ensure every email looks perfect.
  • Be accurate
    ‘Rodney, check this out!’ – my name’s not Rodney ?!?
  • Dodgy characters
    It might look like a hyphen but if you’ve pasted text from Word or similar app it might be a problem. Even worse, it could mess with the character encoding of the entire email. Run Inbox Preview tests to see how it looks in different email clients and mobile devices. 
  • Get user feedback
    There’s many ways to do this but the most obvious way to test subject lines and optimise email campaign response rates in general is to use Split Testing.


Subject lines are a real challenge but with the right approach they are something that you can fairly easily become good at writing.

Always remember not to let the pressure of increasing response rates be the only thing you focus on to the point where it completely kills your copy-writing style.


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