How to write an engaging email subject line

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Email open rates are perhaps the most widely recognized email marketing metrics out there. 1 in 3 people open up emails purely based on what is in the subject line. Crafting the perfect email subject line can be daunting, and the last thing you want to do is deter your readers because of a lousy preview of your content.

Read on how to write a good email subject line that people love, make them open your email, and follow your call to action.

First of all, we want to provide you with a few of our golden rules about subject lines in emails.

  • There is a limit on the length of subject lines in most email clients. While there is usually no (published) limit on how long your email subject should be, we know that Outlook limits the subject line to 255 characters. It is important to remember that not all of these 255 characters will show up in your recipient’s preview list in their inbox or spam folder. 
  • Therefore, your email subject lines should NEVER exceed 60-70 characters. The sweet spot is around 50 characters, which usually equates to an average of 9 words. Remember, nowadays, many people read their emails on mobile devices first.
  • It’s imperative to include a subject line for marketing emails to your email list. No one – let me say that again – NO ONE, will open your email when there is bold text saying “no subject.” There is zero relevance, zero indication of what is inside, and your subscribers will assume you aren’t making any effort.

Okay, so now the question is what to write for your subject lines? If you want to make them engaging, you have to use the kinds of subject lines that make you click on emails or blog posts. Here’s a list of tips to take on board to break things down for you when 

Personalize for every reader

It is said that personalized email subject lines generate higher open rates that are up to 50% higher than non-personalized subject lines. As for your promotional emails, personalized subject lines in this remit still offer email open rates up to 29% higher on average with high click-through rates. Personalized subject lines can be implemented through a variety of techniques, including but not limited to:

  • A subscriber’s name
  • A subscriber’s local store
  • A subscriber’s recent purchase
  • The viewing history of a subscriber 
  • Abandoned cart emails – personalizing based on products left in a subscriber’s cart on your online store.

By using personalization in your subject lines, you are taking more notice of your subscribers on an individual level, as opposed to a one-size-fits-all approach. If personalization per subscriber seems unreasonable, you can always change your subject lines to fit different segments. Segmenting your audience makes it far easier to group local stores, recent purchases, and those with abandoned carts. From here, you can amend your subject lines for groups, not individuals, which will take far less effort, all things being well.

Create a sense of FOMO (Fear of missing out)

Want to make people open your emails with urgency? Use a subject line that makes subscribers feel left out if they don’t open your email. Your readers will probably not want to miss out on a freebie or discounted product/service depending on your industry or product range.

More than half of people will experience FOMO when engaging with marketing/sales emails, so it is a great tactic used by all companies. FOMO can be strengthened, too – By adding urgency to your subject lines, you can give off the impression that readers need to act NOW before it’s too late. The gravity in FOMO subject lines gives you a chance to promote discount periods and free trials purposely. 

FOMO doesn’t need to be time-related. They are often used to offer a limited number of tickets, discount codes, free trials, vouchers, etc. Whatever scenario you end up opting for, it is essential to know that FOMO subject lines have proven to be very useful for conversion rates. Sixty-eight percent of email users have made at least one reactionary purchase due to their response after seeing a FOMO email subject line.

Using emojis in your subject lines

We all know how popular emojis are on social media applications like Facebook, Snapchat, and Instagram, but they also help with email. Using emojis in your email subject lines can help resonate a more emotional or visual feel to what you want to say in 50 characters.

This technique must be taken with extreme caution, though. Emojis in subject lines will rightfully draw your email subscribers’ attention, but it might not always be appreciated. Try not to use emojis that are unrelated to what you are saying. If you are selling clothing, use a shirt emoji. If you are selling holidays, use an umbrella, sunglasses, or an airplane. It’s all about keeping emojis relevant and relatable.

If you offer a discount, a smiling heart emoji might evoke the same kind of facial reaction in the reader, which is a positive response. Try not to assume that emojis will dramatically improve your open rates – like emails in general, they need to be sent to the right person at the right time, and most important, land in their inbox. If you end up in the spam folder, your subject line’s virtually zero chance is recognized as unique – most spam emails contain emojis anyway.

Create curiosity in your subject lines

There is nothing like an email subject line that leaves you stumped and wanting to find out more. Subscribers have specific interests, and by “dangling the carrot” on them, you can make them want to read on and even click-through to your website or store. Curiosity subject lines should generally be a little shorter and blunter because the trick is not to give much away at all. For example, “you’re invited” is very straightforward, but it addresses your readers directly, without actually giving any indication of why you are contacting them.

This technique has its risks, as some subscribers may see it as a phishing type of email. Don’t overuse these kinds of subject lines; use them when you have a new product release, a limited time offer, or anything that can directly involve your subscribers. Remember, the trick is to give nothing away in the subject line – it should boost your open rates and give you more space and options for what to put in your actual copy.

Offering a line of social proof

Subject lines that include social proof can build instant trust with some of your email subscribers. Nearly two-thirds of consumers will buy from companies that have real product reviews and positive recognition. These should be used in your subject lines as evidence that your products are excellent and help your customers enough to offer their feedback.

The two main ways to use social proof are:

  • Customer testimonials and success stories
  • Company awards and evidence of recognition

Social proof in your email subject lines is a trust builder, and we encourage that you use it more often, especially with those segments in your mailing list that have yet to buy from you. Remember to back up the social proof with links in your email’s main body, or else it merely looks like a hard sale tactic. Use your copy to explain how your customers have benefitted from your products, which is the most crucial part of any product’s purpose.

What NOT to include in your email subject lines

Despite there being many ways to boost your open rates in subject lines, there are elements that you should avoid using when you send an email. Subject lines are arguably the most decisive part of your emails, so making the first impression count is imperative. Here’s a list of what to avoid:

  • Using too many characters – This will cut off your subject lines before any will be able to read or even see it.
  • Excessive use of CAPS. – Simply put, capital letters make us think people are screaming or shouting, and when capital letters are used excessively, it sounds more demanding to your subscribers. No one appreciates a rude subject line or hard-sale kind of approach “BUY THIS NOW” “OPEN THIS EMAIL.”
  • Too many exclamation points – This one is self-explanatory; exclamation marks will once again appear like a scream/shout towards your readers, instead of speaking naturally and getting on their level. Avoid this, so your open rates don’t drop excessively.
  • Trickery techniques (e.g., RE, FW) – Trying to appear as a brand that the customer has contacted before is unhealthy and will reduce trust if you try it too often. Pretending that you are replying to your subscribers will only confuse them and make them warier of your brand. Trickery in email subject lines often gives open rates more than 40% lower than regular email subject lines.

Are you looking for inspiration for your next email subject line? We have compiled a list of 22 excellent email subject line examples for you to check out here.

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