Did you know that 69% of recipients report emails as SPAM based solely on the subject line? How about the fact that 47% of people OPEN emails based on the subject line alone? 

Subject lines are the most powerful element of your email marketing campaign. They are the first thing your recipients will see and the biggest factor in whether or not they will open your email. Overall, they are your make-it or break-it moment. However, there are certain subject line mistakes that all email marketers should avoid.


“Subject lines are like newspaper headlines or a title on a book’s spine. They tell the recipient what it is all about and they should do so in sparkling style – seamlessly channelling your brand. ” – Win Goodbody

As an email marketer, you are well aware of how incredibly powerful subject lines can be. After all, your email’s subject line is the recipients’ first interaction with your brand. As such you need to ensure you are striking the right balance between informative and engaging but also succinct and tempting. Unfortunately, your efforts can often be inconsistent leading to unsatisfactory results. The reason lies with some subject line mistakes you might’ve not even considered when crafting yours.

In this article, we’ll cover the following topics on email subject line mistakes :

  1. What are the ingredients of a perfect subject line?
  2. Tried-and-tested email subject line templates
  3. Email subject line mistake to avoid at all costs

Ready to dive in?

Writing the best email subject line is an art and as an email marketer, you need to master it to achieve the desired results with your email marketing campaign. Yet, a lot of marketers and businesses do not give it enough attention which ends up harming your sender reputation and sending your emails straight to the spam folder. 

You certainly know that the more your emails are reported as spam, the less deliverable any of your future emails will be and this will have a dampening effect on your ROI. However, there’s no need to panic. As long as you know the most common email subject line mistakes and pitfalls, you’ll be able to prevent them. 

Some marketers believe in the incredible power of email subject lines so much so that they think that – 

a) a misleading email subject line is worth it to get the holy grail – an open;
b) a perfectly crafted subject line can make up for the lack of permission;
c) if your email does not get opened it is like it was never sent.

As fantastic as these might sound, none of them are true. The goal of your email subject line is not only to generate opens but to generate openers which are likely to convert. Furthermore, your email’s subject line doesn’t only impact your open rate but all other email marketing KPIs. Lastly, your emails are not ads, they are a part of a permission-based relationship. Thus, it’s not only crucially important to have the subscribers permission but it’s also a legal requirement.

Before we reveal the thing you must avoid in your subject lines and tell you how to fix any subject line mistakes, let’s take a brief look at the basics, shall we?

Email Subject Lines: The Basics

Let’s take a look at the common ingredients that will jump out at people when they are scrolling through their cluttered inbox. The biggest ones to consider are – 

a) Curiosity – Does it pique their interest and make them wonder what the rest of the email might say?
b) Urgency – Why should they open this email right now? What’s the hurry?
c) A tempting offer – What awesome rewards does your email hint at?
d) Relevance – Are you giving the reader the impression you’re speaking directly to them / their tribe?
e) Novelty – Are you telling them something surprising or unusual – a cool story or a shocking discovery, perhaps?

You won’t be able to squeeze all these into your email subject line – nor should you try. After all, you need to keep it short, punchy and tempting. However, these ingredients can inspire you to craft subject lines your recipient will not be able to resist and will be forced to open your email.

Email Subject Line Templates

Have you ever had that sinking feeling of spending a whole day crafting the perfect email with the best email subject line and when checking the results your open rate was disappointingly low? Depressing, we know. But you are not alone. However, we have seven amazing tried-and-tested email subject line templates you can take advantage of.

1) The FOMO 

No one likes to feel like they’re missing out, so a top way to create a sense of urgency and inspire action is to create the impression of scarcity or an offer about to end.

2) The Self-Improvement

A dependable classic. Promising people they can be a better version of themselves isn’t new, but boy does it work.

3) The If-Then

If you know your target audience well enough, then you’ll have a good idea of which characteristics they share (see what I did there?). Take something that feels specific but applies to the vast majority, if not all, of the people on the list and makes them think ‘Oh wait, that applies to me!’ Then link this to the solution you’re emailing them about.

4) The Free Gift

Giving your recipient the impression that something real and tangible is waiting for them is always a winner and a great way to cut right through the noise – especially if you personalise it.

5) The Cliffhanger

Humans are curious creatures. Create a little mystery or suspense and we can’t help but peek inside. Don’t believe me? Scroll to the bottom of this page to find out why.

6) The Direct-Informal

This is an increasingly popular method, with good reason. The idea is to mimic the way real people write subject lines to each other, be they friends or colleagues.

7) The Conversational

You need to exercise this with caution. Making an outlandish claim or questioning a popular belief is a great way to get clicks… just make sure you aren’t overdoing it, or you’ll lose people’s trust!

There, you have it. You are all set to take your mailing list by storm. But, we did promise to reveal the most common subject line mistakes and how to fix them so here we go…

Common Email Subject Line Mistakes (and How To Avoid Them)

Good email marketing starts with the perfect subject line and good subject lines are quite easy to create if you follow our guidelines and have an understanding of what your recipients are interested in. Nonetheless, there are certain email subject line mistakes all marketers should stay away from if they want to boost open rates, have happier customers and increase their ROI.

1) Shouting at recipients and excessive punctuation

We all know that ALL CAPS signifies shouting. Thus, better steer clear of overusing it in your email subject lines. 

None of your recipients wants to see an email in their already cluttered inbox that appears to be screaming at them like “GET 30% OFF YOUR NEXT ORDER – NOW”. As awesome as your product/service is and as excited as you might be to share it with your subscribers, you don’t have to get their attention by screaming at them. If you do it will not only appear as rude but the chance of your email getting ignored, deleted or marked as spam are quite high thus hurting your open rate.

The Fix

If you want to emphasise the importance of your email use acronyms like IMP/IMPT or STAT to signify an immediate action/response is required; FYI for purely informative content without any further action required; or, ACT for email campaigns that need further action. Here are some examples – 

  • FYI: Updated employees holiday calendar
  • ACT: Complete and return the attached survey by September 15, 2020
  • STAT: Production malfunction on line 5 requires immediate action

The use of excessive punctuation is also a big ‘no-no’ – “GET 30% OFF YOUR NEXT ORDER – NOW!!!!!!!!!!!!”. Instead of scaring – and possibly annoying – your recipients with an overuse of exclamation marks, emphasise the importance of your email by using the aforementioned acronyms. They will just as easily drive the point home if the spam filters hadn’t already binned your email, of course. 

However, if your email answers relevant pressing matters of interest to the recipient, feel free to craft your email subject line as a question. The use of a question mark (?), in this case, has proven to boost open rates because human beings are curious by nature. For example, if your subject line says “Do you know what percent of email opens happen on mobile?”, the recipients won’t be able to calm their urgent curiosity resulting in them opening your email. See what we did there? It’s a cliffhanger subject line creating both curiosity and urgency.

2) Special characters, symbols and emojis

Special characters and symbols like $, %, &, @, and # are viewed by both the recipients and the email clients’ spam filters as well… spammy. Using them in your subject lines can end up sending your carefully crafted email into the not-so-special spam folder – and that’s not something you want, is it?

Additionally, as much as emojis boost open rates (according to stats, 56% of brands have seen some sort of a boost), they have limited application and you should be vigilant about using them in your subject lines. Don’t forget, not all email clients render emojis. You might end up sending out a campaign with quite a lot of boxed symbols (☐) in the subject line. 

The Fix

If you feel it’s necessary and relevant to your content, do yourself and your recipients a favour, and use special characters and symbols – as well as emojis – in the email body instead of the subject line. But do so sparingly. They have been known to trigger spam filters. Craft your email subject line to be punchy, clever, curious and urgent without using cheap tricks.

3) Spelling and grammar mistakes

Nothing says sloppy and unprofessional like an email subject line with spelling and/or grammatical errors or misplaced punctuation. Would you even open an email with a subject line like “Decorate your hoe this Christmas” or “We need your contamination please…”? As funny as such subject line mistakes might be, they only showcase your lack of attention to detail and if you can be bothered to ensure such mistakes are non-existent, why should the recipient bother with your email in the first place?

The Fix

Your subject line is your chance to make a good first impression, establish – and solidify – a relationship with your customers and build trust. Instead of rushing through it just to meet a deadline or pacify your management’s urgency to send, take the time to spell check not only your subject line but your email’s copy as well. It’ll not only ensure your email looks professional but also boost your open rates.

4) Spammy words/phrases

Email subject lines are like gatekeepers. If you want your email to get opened, you need to make sure it will avoid the spam filters or it’ll never reach your targeted audience resulting in damaging your sender reputation. Furthermore, we all know that a bad sender reputation results in poor email deliverability leading to decreasing ROI. 

The Fix

To keep your emails out of the awful spam folder make sure to avoid the use of spammy words and phrases such as act now, order now, affordable, free, money, win, sign up, now!, bonus, one-time offer, guaranteed, increase sales, limited-time offer, no investment, no obligations and hundreds more.

There might be tons of recommendations of what to and not to use in your email subject lines. What works for one industry might not necessarily work for another. Thus, make sure to always, always test your email subject line before sending your campaign. 

5) One word or extremely long subject lines

Depending on the screen your recipients are viewing your email, subject lines can appear differently as the real estate for it is limited. 

On desktop inbox, you can see 60 characters (sometimes even more) of an email’s subject line, while mobile devices will reveal 25 to 30 characters. With such limited space, as an email marketer, you must ensure that your email subject line is neither too short (one word) or too lengthy. Otherwise, you risk changing the message in ways that are either distracting and confusing or embarrassing and, sometimes, even funny. 

One word subject lines like “Important” or “Survey” or just “Hi” can not only miss the mark on what your email is all about leading to lack of it being opened but also it can be viewed as spammy. In either case, despite your desire to make it efficient, you will lose the recipients’ attention and they’ll simply ignore/delete your message.

Additionally, overly long subject lines are not a good idea either. Keep in mind people lead quite busy lives driving them to quickly scroll through their inbox instead of examining it thoroughly. Here are a few examples of quite lengthy subject lines – 

Subject Line Mistakes: Things Marketers Should Never Do | EmailOut.com - free email marketing softwareSubject Line Mistakes: Things Marketers Should Never Do | EmailOut.com - free email marketing softwareSubject Line Mistakes: Things Marketers Should Never Do | EmailOut.com - free email marketing softwareSubject Line Mistakes: Things Marketers Should Never Do | EmailOut.com - free email marketing software

The Fix

According to our uber-smart friends at Litmus, the best/recommended length for a subject line is no more than 50 characters. Thus, you need to make sure your subject line will get your message across quickly creating urgency and forcing the recipients to open your email. Avoid writing subject lines that are too short, too. No one will open an email that simply says “Survey!”. It’s neither considered helpful nor relevant to your subscribers. Of course, professional ESP(s) – like EmailOut – give their users a free inbox tool where they can see what their subject line will look like in over 70+ email clients as well as on mobile devices. 

6) Misleading or vague subject lines

Your recipients’ inbox is overloaded with all sorts of emails – from informative to sales ones. Don’t try to get them to open yours by misleading them and using deceptive or vague subject lines to do so. That will only get your email reported as spam and then deleted.

For example, if your subject line says “Get an exclusive discount off all of our services” and when the recipient opens it and it pitches them to sign up for your newsletter or a free webinar, trust me, they will get annoyed and the consequences will be damaging not only to your sender reputation (they will report the email as spam – for sure) but also to your brand’s reputation and image. It’s a dishonest and deceitful tactic that will backfire 100%.

The Fix

Write a subject line that aligns with your email’s content. Don’t trick recipients. Instead, be honest and clear about the intentions of your message. It’ll not only build a trustworthy relationship with your subscribers but also improve your credibility and sky-rocket your open rates. Just deliver on the promise you outlined in your subject line. Ah, and remember, cheap tricks like including “RE:” or “FW:” to your subject line to fool the recipient into thinking your email is a part of previous communication is a serious ‘no-no’. Did we also mention that misleading and vague subject lines will bring you perilously close to violating CAN-SPAM laws? 

7) Ignoring the preheader

Your email preheader, also called the preview text or snippet, is the line of text that appears under the email subject line when emails are displayed in your inbox. If you’ve designated a particular line of text as a subheader, it will appear just below the subject line. Otherwise, the recipient will see the first line of text from the email body itself.

Many marketers either don’t have a clue of what it is or don’t bother to pay enough attention to it. The latter being a huge mistake as the preheader will help your subject line drive the point home giving you one more chance to persuade the recipient of the importance of your email. 

The Fix

Most professional ESP(s) allow marketers to choose the preheader of their email campaign instead of just pulling it from the first sentence, an image alt text or default browser instruction. Instead of leaving it to chance (because you didn’t even think about it), make sure you’ve crafted your preheader as carefully as you did your subject line. After all, as we said already, it’s your second chance of driving the point home. Don’t miss it.

Final Thoughts

Your email subject line is like a movie trailer – it should give your recipients enough information but leave them wanting more. It should grab their attention, create a sense of urgency and convey the importance of what you are offering them, be it a discount, limited-offer, special access to features, tutorials, webinars, etc.

However, everything is not always hunky-dory. Ultimately, we are all bound to make a mistake or two. But, when you know what to be on the lookout for and how to fix it, nothing can stop you from reaching success. So, instead of panicking and pacing your office space nervously (show mercy to your shoes), make sure you learn all the email subject line mistakes we told you about – and, of course, how to fix them.

Highly recommended further reading – 

1) Top B2B Subject Lines
2) Email Subject Lines That Deceive
3) Permission-Based Email Marketing
4) Why Do You Need To A/B Test?
5) Top Split Testing Tips
6) The Ultimate Email Preflight Checklist
7) Email Preheader Mistakes To Avoid

*Did you scroll to the end to find out why? See! We just can’t help ourselves!

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