8 Tips to Write a Killer Email Subject Line

A mailing list is a valuable marketing tool for authors – but only if your readers open the emails. One of the best ways of getting a good “open rate” is by writing an enticing email subject line to pull readers in.

Here are eight rules for email subject lines that will boost your open rate.

1. Keep the email subject line short

If it’s too long, it risks getting cut off in the email program. Set a maximum length of around 50 characters.

For example:

“Discover why Nathan Harding is out to kill” (43 characters) instead of: “The real reason why Nathan Harding is on a mission to kill” (59 characters).

Edit your subject line to make the benefit to your reader immediately clear. Aim for a pithy style to make each word count and experiment with deleting articles or prepositions.

Think news headline style, rather than Dickens. Some successful subject lines are just a few words long.

2. Be relevant

What you write should be in line with what your readers want. Always have in mind: Why did they subscribe, and what are they interested in? Bearing that in mind as you write will keep your unsubscribe rate low.

If you write in more than one genre, consider having more than one mailing list to avoid sending information that isn’t relevant to your readers’ interests. You’ll definitely want to do that if you write and publish under more than one pen name.

To make sure your email subject line is relevant, get into the habit of writing the reason why the reader should open the email. Often you can combine this reason with a list. This is especially the case for “how to” type emails, but you can also use it for fiction-oriented lists:

How to Snag a Millionaire (for romance writers)

5 Reasons Why I Killed Off Detective Jones

6 Sales Strategies for Authors

Two good words to use to get clicks include “quick” and “easy”.  For example,

6 Quick Links to Find Half-Price Books

If it’s hard to think of a specific reason why your reader should open your email, try targeting your subject line to your reader and their interests.

For example:

For Fiction Fans Who Like a Twist In The Tail

Mid-Week Meals for Time-Challenged Cooks

Think about why your reader should open your email. What’s in it for them? What will they be able to do after they read it? How will what you tell them benefit them?

By including the benefit in the subject line you’ll also be focusing on staying on message in the email itself. This is why subject lines like How I write 1000 words an hour or Launch Your Novel in 30 Days are so effective: they speak directly to our concerns as writers.

3. Make the subject line interesting and descriptive

Work on the assumption that your reader gets too many emails to read each one. That means an appealing subject line is the only way you have to stand out and be clicked.

Don’t use passive or weak subject lines. Avoid subject lines like Weekly Update or Quarterly Newsletter, for example.

4. Pique curiosity

A simple way to do this is to include verbs like “discover”, “get”, “grab” or “learn”.

You can also hint at a secret you’re going to reveal, mention a sneak preview or give some insight into a character or plot development:

Heroine Finds Herself In Scalding Hot Water (ie for romance / character development)

House-hunting? 12 Scams To Avoid (for non-fiction writers)

You can also experiment with provocative subject lines. Why You Aren’t My Favorite Reader might well cause a reader to open in surprise or shock.

Vary your email subject line. Include direct questions, teasers, or even humor if you think your readers will appreciate it.

5. Avoid being too salesy

Beware of words that make your subject line seem like spam. They may trigger automated spam algorithms, sending your beautiful email to the junk folder. Messages with words like “Free”, “VIP”, “Discount” can all get your email binned. That’s not to say you can’t use them, but use them sparingly.

6. Use tried and tested psychological factors

For example, using questions in your subject line will hook readers right from the start. Alerting your reader to a countdown deal emphasizes urgency, and harnessing the concept of “social proof” (“20+ 5-star reviews already”) or  “10 Weeks on the Bestseller Lists” can legitimize a reader’s impulse to click open the email.

7. Play around with capitalization and punctuation

Don’t write an email subject line all in capital letters, but you can include one word in caps if it’s sufficiently important.

Some punctuation (like exclamation marks) are better left off, but questions can work – especially as they involve the reader.

Are you ready for NaNoWriMo?
Are YOU ready for NaMoWriMo?

8. Be timely

When you send your email can have an impact on whether it’s opened.

5 Page-Turners for your Summer Holiday Reading (in early July, for example)

Apart from tying in to national or relevant dates, consider when (in the day) you send your email, and how often you’re contacting your readers. Too frequently and you might get a lower response than expected.

Another way to be timely is to include new information in your subject line.

New Book in The Lovelorn Series: Get Your Copy Now

This is also the case if you’re offering exclusive content to your readers:

Exclusive Chapter Just Released

You can also play the urgency card. Marketing expert have known for years that phrases like “Limited Offer” encourage actions like opening an email because readers are anxious not to miss out.


Co-founder of Publishing Spark.

We help fiction and non-fiction authors grow their readership with a simple-to-use, no-hassle mailing list service. Check us out.

8 Tips to Write a Killer Email Subject Line

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