How to write killer email subject lines?

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How to write killer email subject lines?
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Deliverability, an email-marketing expression, represents half of the work necessary to achieve an opening rate of over 90%. The rest comes down to the choice of email subject lines. 😉

This article will help you to:

  • Create effective emails with good subjects that convert.
  • Generate a higher click rate in your emails so as to boost the open rate.
  • Write catchy email subject lines and headlines.
  • Create a great email marketing campaign.
  • Get more subscribers on your product.
Without the right recipe, your emails, no matter how well delivered, are likely to fall into oblivion for lack of sufficient interest from your audience…
In this article, we are about to share our secrets to find the best possible subject lines for your campaigns. 😎
This article was written in partnership with Scalezia. Scalezia helps startups, scales-up but also SMEs implement the latest growth methods to create sustainable growth and internalize these skills, in order to make the company autonomous in the long term.

They also offer a huge range of free content, covering all the important topics of acquisition but also content creation, product market fit research and many other topics that are essential to grow a business. To access their courses, click here (you won’t regret it).

1. Nature and function of email subject lines

Before starting the actual task of writing, you have to understand the role played by the subject line. And it wouldn’t be an exaggeration to say that misunderstandings regarding the email subject line are endless.
No, its function is not to generate a conversion.
No, it is not to create a desire to buy.
No, it is absolutely not, either, to give visibility to your brand or your website.
In fact, there is no object less effective than those using a structure and a tone resolutely marketing.
Let’s do a little brainstorming:
  1. To start with, think back to the last ten emails you opened: what is the ratio between emails sent by physical persons (colleagues, relatives, partners) and legal persons (companies via newsletters and other transactional emails).
  2. What did the subject lines of the emails you received from individuals look like?
It is very likely that this ratio is very strongly in favor of the latter, and that the subject lines of these emails combine concision, abstraction and informality. We will come back to these points later.
You opened these emails for two reasons. First, they were sent to you by individuals, not companies. In an era of constant overexposure to marketing and advertising, you have developed protective filters that help you sort out, or even ignore, commercial solicitations.
Secondly, the short, abstract subject lines have made you curious enough to open the email and read the content. What important information could be hidden behind this iconic “follow-up”?

This brings us to the very function (and above all: the one and only function) of the subject line: to create curiosity to generate an opening.

2. Psychology and cognitition of email subject lines

Over time, our brain has built up filters that allow it to quickly analyze and filter incoming emails based on a minimal amount of information. Thus, a simple reading of the subject line and the sender is enough to determine the degree of urgency and priority of its content. 👽

As a result, your subject line is able to categorize your email into three mental “folders”:

1. Polluting emails, which bring nothing and cost more than they bring

2. Non-urgent emails, to be consulted later “when we have time” (i.e. never in 90% of cases)

3. Urgent emails, to be consulted right away in order not to miss an important information.

It is crucial to fall into the third option. To do this, you need to empathize with the other person’s way of thinking about their emails. Every professional checks his or her inbox.

For one simple reason: to get information that will help him or her get to the task at hand. Whether it’s to work more efficiently by coordinating with colleagues, to identify new opportunities that will allow them to gain value within their company, or to learn about important information that needs to be addressed urgently in order to avoid potential problems that could have been prevented (and thus avoid getting a slap on the wrist from their boss/team). 👌

Thus, for each email, a recipient will govern their decision making with the following question: “Of the items available, is this email likely to help me in my work? Can I find something in it that will help me achieve my goals, or is it information that will harm me if I don’t read it right away? ».
Yes, and the email will be read. No, and the email will at best be ignored, at worst deleted or marked as spam.
The key is to produce a subject line that suggests either urgency or opportunity. The key here is the idea of suggestion. We will try at all costs to avoid anxiety-provoking objects and other false promises in order to establish a healthy relationship and a high level of interpersonal trust. The idea is to play on the abstraction of the object in order to let the recipient’s imagination do the rest of the work.
As you can see, producing an object is not a matter of chance and is the result of reflection on the aspirations and behavior of your audience. A well-mastered and intelligent play on their fears and aspirations is a particularly effective way to get them to open and read the email with interest and attention. However, be careful not to overdo it. For example, avoid explicit subject lines such as “URGENT”, which may cause understandable annoyance to your audience.

3. Key editorial concepts

The objective here is not to sell, convince or persuade. The content of your email (once it is opened), the quality of your supporting materials and your marketing skills will be much more likely to achieve this.
Why do you want to do this?
To answer this question, you’re going to use a few lines to do some copywriting. This is the art of writing to entice your reader to perform a specific action, whether it’s a sale, a registration, a donation, or any other action leading to a more advanced relationship. This discipline, as rich as it is complex, is governed by a multitude of psychological mechanisms and writing models, also called frameworks.
Of the most commonly used (and most effective) frameworks, the most notorious is AIDA, which consists of a sequential alignment of elements seeking to:
  • A: Grab the reader’s Attention to get them to interrupt their current activity in order to consume the rest of the content – we’ll seek to answer the question “what’s in it for me.”.
  • I: Create Interest by bringing in a specific issue, which we will try to make as palpable as possible so that the reader feels as concerned and emotionally involved as possible – we will try to answer the questions “what is the issue at stake? ” and “am I concerned by this problem?.
  • D: Make the reader want to solve the problem by proposing a solution to the problem described – question: “How can I solve this problem in a safe/ profitable/ fast/effective/healthy way? ».
  • A: Finally, invite the reader to perform a specific Action that will allow him/her to obtain the said solution – question: “what should I do to quickly obtain the solution presented? » Attention. Interest. Desire. Action. In that order. A formula so effective that it is found in the vast majority of persuasive writing.
So now you know: the subject line of an email has no other function than to grab the recipient’s attention, so that he or she will interrupt his or her inbox scrolling session to read the rest of the message.

4. Write email subject lines that open

But then, why do you prefer short, abstract and non-marketing-sounding subject lines (subject titles)?
Simply because the channel is not adapted to it.
A classic mailbox is made up of 3 main types of content:
  1. Solicited marketing emails (newsletters, transactional emails…): these are emails that the recipient expects to receive and knows the sender.
  2. Unsolicited marketing emails, which generally have little impact, and often end up as spam, for the simple reason that their reception goes hand in hand with the unpleasant feeling of being part of a mass of contacts clumped together in a mailing list.
  3. Interpersonal emails, exchanged from one individual to another, which go hand in hand with the feeling that the interlocutor has taken the time to write the email received, to us and to us alone.
It is in this last category that you are looking to place yourself. And, if you look closely, these are usually introduced by again short, abstract and informal objects.
So, of the thousands of objects we’ve tested over the past few years, the ones that work best on our end (across different personas and industries) are:
  • Email 1: “Intro.
  • Email 2: “Re: question.
  • Email 3: “follow-up.
  • Email 4: “(no subject)”.
Each of them generates 70% of openings on average. On the scale of a campaign, it is therefore almost inevitable to reach 80% or even 90% of openings, provided that your deliverability is optimal. You have seen it: the above objects do not make any promises. There is no more deleterious practice than that of overselling the ins and outs of an interaction. Avoid at all costs “clickbait” objects that risk misleading your audience and will cut short the relationship of trust you are trying to create.
The possibilities are endless and it is crucial that you find objects adapted to your audience and the context of the contact. For example, if your contact is about your contact’s website, you can test objects such as “Site {company}”, “Question {domain}” or simply “Site”. In the same idea, if you are sending a reminder consisting of sharing a high value video, you could simply use “video”.
These choices emulate the way any time-sensitive individual introduces emails: with speed, simplicity and disinterest. “(no subject line)” is an example taken to the extreme.

As you can see, the objective here is twofold. On the one hand, it is to arouse the recipient’s curiosity in order to get them to open and read the message. On the other hand, we seek to lay the foundations for an interpersonal relationship, more likely to lead to conversion. Attracting and arousing attention is at the heart of our considerations. PS. You have a lack of inspiration? Don’t worry: we’ve prepared a list of subject titles that will allow you to get at least 70% of openings. Just click here to access it. 🌳

5. Test your email subject lines

Nevertheless, and you know this as well as we do, marketing is not very comfortable with techniques that are copied without any nuance. It is crucial that you find your own subject titles, i.e. those that resonate with your audience enough to offer you the best results. The best way to do this is to test a lot of items. Here’s an example of a campaign we ran:
    • Email 1 – A: Intro – Linkedin / B: freelancing question.
  • Email 2 – A: Re: question / B: follow-up.
  • Email 3 – A : link / B : info.
  • Email 4 – A : (no subject) / B :'(.
The same campaign was duplicated 4 times. With 8 objects per campaign, we managed to test no less than 32 different objects, which allowed us to quickly find the objects that worked best at each stage. The next step will be to compile the best performing items to produce a super-campaign of the best items, which will guarantee the highest opening rates.
But be careful: don’t make the mistake of looking at open rates alone. It is crucial that the response rate is also taken into account. Indeed, it can happen that an object generates a high opening rate but negatively influences the response rates. Therefore, make sure you select objects that guarantee high rates in both cases.
Now you know how to write snappy email subject lines! 🚀