The Secret to Great Email Subject Lines


I have written quite a few marketing emails for clients and one of the most critical questions I must consider is what type of subject line will yield the highest engagement (i.e. open rate). There are many schools of thought here. In all my research, I’ve found exhaustive breakdowns, trends, data, and recommendations from various sources that can lead to more questions than answers. Each piece of advice in its own right seems compelling, even proven. Yet, as I continue to research I can easily find another source that feels the exact opposite approach is best. Sure, much of this can depend upon what you’re trying to “sell” and your industry, but there has to be some common ground where data can agree on a few main points. Right?

I do believe so, which is why I scoured various reliable and respected email marketing sources to pull the recommendations for effective subject lines that agreed (at least somewhat) across the board as “golden rules” that should be followed. Keeping reading to find out what they are.

Avoid Being Confused for Spam

According to Optinmonster, 47% of email recipients open an email based on the subject line alone. And 69% of email recipients report email as spam based solely on the subject line. Some research I came across claims using language in an email subject line like [Urgent!] or [Don’t open this email!] or [I need your help today] plays on recipients’ curiosity and entices them to open the email. But email platforms are only getting smarter and more aggressive with how they identify spam. In my opinion, this tactic is not worth the risk of sending a massive amount of your emails into spam folders even if it entices a few extra opens from the low percentage who actually receive it. Additionally, data across the board agrees that the best way to write email subject lines for higher opens (instead of being marked as spam) is by leveraging natural human tendencies and psychological principles.

Follow Human Tendencies

So what are human tendencies as it pertains to email subject lines? Emotions and desires! Fear, humor, curiosity, love, belonging, even greed can be worked into an email subject line. Below are just a few categories of human tendencies that you can explore with your next email subject line and an example of each. Always consider your customer base and what you’re trying to sell, then match this up with the best emotional appeal to use.

Fear of Missing Out – “Your reward points expire at midnight…”

Curiosity – “Did you know this is the highest paid job in marketing?”

Pride – “Don’t wear last year’s styles.”

Humor -“Where to Drink Beer Right Now” (Sent at 6:45am on a Wednesday.)

Greed – “A little luxury at a great price”

Laziness – “Grow your email list 10X faster with these 30 content upgrade ideas”

Pain – “Stop wasting time on mindless work”

Connection – “[Name], let’s have lunch. My treat!”

This should hopefully give you a little inspiration for how these various human tendencies play into email subject lines, as well as which ones might be most effective for your next marketing email. And there are many more beyond this example list!

Tread Lightly with Emojis

According to a report by Experian, using emojis in your subject lines can increase your open rates by 45%. However, it’s recommended by pretty much every major email platform to use one emoji at most, and don’t use one for every single email. An emoji is a fun and colorful change-up to your usual subject lines, but it can begin to look like spam, even juvenile if you begin cluttering inboxes with these little icons. I do like a relevant and well-placed emoji in a subject line! And personally, I feel like this entices me to pay attention to the subject line. Explore the use of emojis for your business, but use the best practices of including no more than one and be sure it makes sense in the context of your subject line.

Cut to the Chase

It’s okay to be direct in your email subject lines. While you might think these are considered “boring” subject lines, data says otherwise. Subject lines like “[Company Name] Sales and Marketing Newsletter for March” has been proven to yield consistently high open rates. Apparently people like consistency and when businesses cut to the chase. Don’t assume you need to bait people into reading your content. If you deliver quality content on a regular basis, your engaged subscribers will look forward to hearing from you – and without all the gimmicks. For some industries, yes a little bait is a good thing. But for many others, being direct with your customers earns loyalty and respect.

Like anything, take this advice with a grain of salt – and use common sense! You know your business and customers the best, or at least you should. Embody them as you brainstorm options for your email subject lines. Then conduct your own trial and error! Test out the advice above and monitor your analytics. And never hesitate to speak with someone who knows more than you do. That might be the simplest and smartest business advice of all time. The bottom line I wish to express is email subject lines *do* matter. If you’re not seeing the results you desire from your marketing emails, first look at your open rate. If it’s low, your approach to email subject lines may be to blame (among other things that are long enough for another blog post). 

What’s the biggest “mystery” you need to solve in order to raise the effectiveness of your email marketing? Or do you have another piece of advice to share? Join in the conversation by leaving a comment below.