Consumers have become desensitised to email marketing, which is why small businesses should make their correspondence stand out with excellent content.
Bob Hallewell, founder of consultancy Expert Messaging, said the repetitive nature of receiving email marketing means many people skim or delete messages without even reading them.
Even offering discounts and special offers in the subject line may not be enough. Mr Hallewell likened ineffective email marketing to receiving similar takeaway leaflets on the doormat every day. Instead, messages have "got to appear relevant and not just as another offer to the person who gets it".
People pay more attention to content that is highly targeted to their individual needs or, as internet psychologist Graham Jones suggests, where a headline really grabs their attention.
He believes lower open rates for email marketing can be attributed to subject lines that "do not hit home hard enough each time to attract the interest".
Mr Jones believes email subject lines should be approached in the same way that national newspapers, in particular tabloids, create their headlines.
"People need to spend more time and effort on the subject line than they do on the contents of the email. In that way they would get more user engagement," he added.
Email marketing: what not to do
Headlines need to pack a punch, but what should content creators avoid when they write subject lines for email marketing?
Because credibility is such an important factor in content marketing, any headline that diminishes the reliability of the information is a big no-no. Therefore, make sure all content – including the headline – is meticulously spell-checked and proofread so there are no mistakes.
While email content should be written in the tone of voice of your target audience, excessive use of exclamation marks, capitals or the word "free" might not only be distracting to your recipients, but spam filters may block the message altogether.