The Best Email Subject Lines - Avoid These 5 Common Mistakes

The best email subject lines are the ones that get your emails opened. The subject line is not the first thing your recipient looks at. That’s the From name. But after that, the subject line will get your subscriber to open your email—or not.

Research finds 47% of recipients open an email based on the subject line. That’s almost half of the names on your list who will decide to open your email or ignore it based solely on the subject line.

And if your email doesn’t get opened, what’s the point of sending it? Without an open, your email message goes unread. If it’s not read, it’s not acted upon. Any email not opened is an email wasted.

So, take the time to figure out the best email subject lines for your business, those that help your emails stand out among the inbox clutter and get your emails opened—and acted upon.

Make Your Email Subject Lines Relevant

Relevance is key, of course, but there are other ways to up your open rates. Below are the top five mistakes I see marketers make, plus ways to avoid them so that you can create the best email subject lines for the best open rates

5 Mistakes To Avoid In Your Email Subject Line

Mistake #1

Not creating a sense of urgency

It’s important to convey a sense of urgency to prompt your subscriber to open your email. Key words like “this week only” or “for a limited time” are a tried-and-true approach. You could also test wording like “last chance,” “early bird special,” or “extended offer” to see how they perform for you.

Mistake #2

Not saying “Thank You”

Studies have shown that using Thank You in your subline dramatically increases the open rate. Everyone likes to be thanked and those two words can help increase your open rate as a result. Try weaving “thank you” into your subject lines with an A/B test, one with and one without, and compare the results.

Mistake #3

Your subject line is too long

With our declining attention spans, a subject line that is more than 10 words just won’t drive the results. A shorter subject line can help your open rates get to the point. (And see mistake #5 about the short subject line length on mobile devices…)

Mistake #4

Not personalizing

No one wants to feel part of a crowd, just one of many receiving a generic email blast. People want to feel special. When writing the best email subject lines, you’ll treat your subscribers like talking directly to them. Research says emails with personalized subject lines are 22% more likely to get opened. Simply using their first name and a “loyalty” status can increase their likelihood of opening your email.

Mistake #5

Not optimizing for a mobile open

According to EmailMonday, 49.1% of emails are read on mobile devices globally, so optimizing is critical. Many mobile email apps only render 35 characters of the subject line, so make sure your personalization, “thank you” or sense of urgency is upfront. Subject lines under 40 characters won’t be visible until the email is opened.

Investing your time in writing the best email subject lines will yield the results to pay you back for that time. Utilizing your ESP’s ability to do A/B or multi-variant testing will show if you are on the right track as you figure out the best email subject lines for you and your email marketing goals.


Crafting compelling email subject lines is essential for the success of your email marketing efforts. The subject line is a crucial element that determines whether your email is opened or ignored.

You can significantly improve your open rates by avoiding common mistakes such as failing to create a sense of urgency, neglecting to say “thank you,” making the subject line too long, not personalizing, and not optimizing for mobile devices.

Remember, the goal is to make your emails stand out in a crowded inbox. Implementing these strategies and continuously testing and refining your approach with A/B or multi-variant testing will help you discover what resonates best with your audience.

Ultimately, investing the time to craft the best email subject lines is an investment in the effectiveness of your overall email marketing strategy, leading to better engagement and higher conversion rates.