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How to Write Great Subject Lines for Your Marketing Emails

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Read Time: 10 min
This post is part of a series called Email Marketing Jumpstart.
Which Email Type Is Best for Your Business?
Strategies to Boost Your Email Open Rates

You've created an email list because you want to communicate with your customers. For that to happen, your subscribers must open your emails. Effective subject lines get your emails opened. So how can you write effective subject lines?

Why "Attention-Grabbing" Subject Lines Fail

Recently, email marketing software provider MailChimp published research that uncovered a paradox at the heart of email subject lines. For their research, MailChimp analyzed over 200 million emails that were sent out using their software.

At the top end, emails were opened by 93% of recipients. By contrast, the most poorly performing emails had an open rate of just 0.5%.

What did their research uncover?

"Boring" emails subject lines performed best.

The top three performing subject lines were:

  • Preliminary Floor Plans for Southern Village Neighborhood Circle Members
  • Your April Website Stats
  • Idlewild Camp - Important Travel Information

As MailChimp points out, none of these subject lines is particular exciting. But all of them indicate that the email contains timely and useful information.

In a previous MailChimp study, the following subject lines were the top performers:

  • [Company Name] Sales & Marketing Newsletter
  • Eye on the [Company Name] Update (Oct 31 - Nov 4)
  • [Company Name] Staff Shirts & Photos

Again, these are all rather mundane.

By contrast, let's look at the worst performing headlines in MailChimp's two studies. These were:

  • Tempting August NUSA Specials!
  • SALE ends soon - up to 50% off all bras at Kara!
  • Last Minute Gift - We Have The Answer
  • Valentines - Shop Early & Save 10%
  • Give a Gift Certificate this Holiday
  • Final reminder for complimentary entry to attend the West Freelands BCI Cluster Conference 2006

As you can see, all but one of these subject lines is pushing a sales promotion. In other words, the writers tried too hard to be attention-grabbing.

Why does boring succeed where attention-grabbing fails? Because people are tired of being sold to. The average American is exposed to 5,000 marketing messages every day. Little wonder that we've learned to switch off to marketing. We ignore anything—including emails—that try to sell to us. As MailChimp puts it:

Most people get so much junk mail in their inbox, anything that even hints of spam gets thrown away immediately.

So if trying to grab attention doesn't work, what should you do instead?

A Method to Get Attention With Your Subject Lines That Really Works

You want your emails to get attention. But as we've seen, trying to get attention with a salesy subject line doesn't work. Let's look at what does.

Think back to when you last checked your email inbox. Chances are, you opened some messages and archived or deleted others without a second thought. How did you choose which emails to open and which to ignore?

I'd guess you didn't think too hard about it. Most of us deal with over 100 emails a day. So we don't have time to mess around. Instead, we pick out the emails that matter to us in some way.

What makes an email matter?

Every human being has a unique inner landscape. In this landscape are a set of underlying hopes and dreams, as well as fears and anxieties.

An email matters to us when it can help us move towards our hopes and dreams or away from our fears and anxieties.

This is rarely a conscious process. For example, you probably open all emails you receive from your boss. But when you open these emails you probably don't think "I'm only opening this because I want to keep my job, so I can pay my mortgage, look after my family, and maybe get a promotion one day." You're probably also unlikely to think "I'm opening this because I like approval from my boss." But that's a big part of what's going on when you choose to open your boss's emails.

How does this connect with email marketing?

The point is, people open emails because the email connects in some way with their inner landscape. In other words, people open emails that are relevant to them.

In summary, people open an email for one of two reasons:

  • It's from a person or company that matters to them in some way.
  • The subject line is about something that matters to them.

Write subject lines about things that matter to your audience, and you'll get your emails opened.

How to Make Your Subject Lines Relevant to Your Audience

Here are strategies you can use to make the subject lines of your emails relevant to your audience:

  • Get the right people on your list. You'll be better able to target the "relevant spot" if the people on your list are interested in what you have to share. So when you're recruiting for your list using a sign-up form on your website, let subscribers know what to expect. Will you be sending a monthly newsletter? A daily e-course? Offers and promotions? By telling people what to expect, only those who want what you have to give will sign up. That's good news for your open rates.

  • Give what you promised. Let's say you entice people to sign up to your list with a free buzz piece such as an eBook. You know your readers liked your eBook, so they'll appreciate receiving emails with similar content. If instead you entice new subscribers with a buzz piece, then use your list to send out promotions, your subscribers will see you as a spammer.

In MailChimp's study, not all promotional emails performed badly. When subscribers had signed up to receive promotions, then promotional emails sent to that list were more likely to perform well. In MailChimp's own words, "the difference seemed to be in the expectations that were set for the emails."

Delivering on expectations boosts your open rate. It's also good for your brand image. Giving what you've promised shows that you're trustworthy.

Write emails that matter. You can write an awesome subject line that connects perfectly with your audience. But if the content of your email fails to deliver on the promise in the subject line, then you'll lose subscribers.

You could think of it this way. First, write great emails that you know your subscribers will love. Then, use the subject line to share what's in the email. Hence MailChimp's "secret formula" for writing subject lines:

This is going to sound "stupid simple" to a lot of people, but here goes: Your subject line should (drum roll please): Describe the subject of your email. Yep, that's it.

Talk to your subscribers. How can you continue to come up with great content for your subscribers week after week, month after month? A simple way is to ask your subscribers questions. Find out what they'd like you to share. Then deliver.

You can also do this without asking your subscribers. Watch how your emails perform. Notice the types of email that get the best open-rate, then send out that email type more often.

Other Ways to Make Your Subscribers Care

Relevancy is by far the most important factor in whether or not your emails will be opened. Relevant subject lines are what make your subscribers care.

But when you know your email is relevant, what else can you do to give your email the best chance of success? Ramp up the emotional impact. There are several ways you can do that:

  • Provoke laughter. If you're gifted with a funny streak, use it when you're writing subject lines. Most email subject lines are dry—and as we've established, that's not always a bad thing. But if you can get your subscribers to smile, then you can guarantee they'll want more. So they'll open your email.
  • Court controversy. When you know your list well, you know the likes and dislikes of your subscribers. You know what they passionately believe in and what they cross the road to avoid. So use your subject line to say something they'll find controversial. Share a shocking fact or statistic. Use this tactic with care, as you don't want to annoy your readers. But a gentle poke that provokes them to open your messages is never a bad thing.
  • Use the old chestnut: lists. Lists are engrained deep in the human psyche. All bloggers know the power of list posts for getting attention. Lists can work well in emails, too, as they naturally create a click-worthy subject line.
  • Personalize, Personalize, Personalize. Dale Carnegie, author of the classic self development book How to Win Friends and Influence People, famously said: "A person’s name is to that person the sweetest and most important sound in any language." That includes the language of email. Most email marketing services allow you to easily personalize every subject line to include the name of the recipient. Depending on the data you have on your subscribers, you can also personalize subject lines based on the city or state where they live.
  • Ask questions. Few people ask questions in email subject lines, so questions can really stand out. Questions are also great for prompting a reaction.

Does the Length of Subject Lines Matter?

How long should a subject line be?

Research by MailerMailer found that subject lines of between four and 15 characters performed the best, with an open rate of 15.8%. By comparison, subject lines of 16 characters and above had an open rate of around 10%.

Yet according to MailChimp, the length of a subject line doesn't really make much difference.

Shorter subject lines are most important if your subscribers check their emails on a smartphone or small tablet. The smaller screen means they won't see your full subject line. So if you know a lot of your subscribers read their emails on their phones (and that's the way things are going), then keep your subject lines short, or make sure the topic of your email is apparent in the first two or three words of your longer subject line.

How to Never Be Stuck for Ideas

There's no doubt that for email marketers, writing good subject lines matters. But even for the most creative of us, ideas don't always come easily. This is especially the case as there's so much to consider while composing subject lines.

Fortunately, there's a simple technique you can use to ensure that you're never short of ideas.

This is to keep a notebook with a swipe file and an idea garden.

You can keep this notebook using:

  • Pen and paper
  • A Google Document
  • An Evernote Notebook
  • Simplenote

Or any other note-taking technology.

Your swipe file is for collecting email subject lines that you like. Whenever you receive an email that makes you go "I've just got to read that!", add the subject line to your swipe file. Some you'll collect because they were relevant for you (that's a good reminder of how to write great subject lines). Others you'll be able to tweak and recycle in your own emails.

In your idea garden, jot down any ideas for email subject lines you have. You may have these ideas when you're washing the dishes, driving your car, or watering the flowers in your yard. They might also come in spurts. You'll think of a slew of great ideas at once. Don't just take one and lose the rest. Note them all. It's called an idea garden because once you've noted down your ideas, you can wait to see which of your ideas grow into a full email.

In Summary

Effective subject lines for email marketing:

  • Don't try hard to "grab attention."
  • Are relevant to your subscribers.
  • Pack an emotional punch (whether through humor, controversy, or personalization).
  • Are shorter rather than longer.

And you can come up with great ideas by harvesting subject lines from the world around you.

Happy subject line writing!

Learn more about jump starting your email marketing in our multipart, foundational series on the subject.

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