Crafting the perfect email subject line is one of the simplest yet most powerful ways to boost your open rates. In a crowded inbox, even the best content can go unnoticed if the subject line fails to capture attention. That’s why marketers today must balance creativity, clarity, and personalization to stand out. From real-world examples to strategic use of AI, there are proven methods that can transform your email performance. In this guide, we break down the most effective best practices to help you write subject lines that get clicked every time.

1. Learn From Successful Email Subject Line Examples

When in a dilemma or brainstorming on the subject of an email, I tend to refer to examples in order to get an idea of what to use. Having witnessed brilliant wordplay or emojis on one of our preferred newsletters can also make us consider how we can be more creative with our subject lines. To assist you in doing the same we have provided a list of 100 email subject lines used by actual businesses. Hopefully, you will be as inspired.

2. Get to the Point

 An Anthropologie email subject line that writes, It’s Happy Hour, and has the cocktail glass emoji. As I said earlier the email subject lines will be trimmed down in case they are too long especially when using cellular devices.

Given that 55 percent of all emails are read on mobile, we suggest that you use subject lines that contain less than 50 characters so that those that scan through your mails can read the whole message.

In case you have a hard time keeping your subject lines concise, consider the words that are less important and the places where you can cut a wasteful piece of information. As an example, when you are sending out an order confirmation, does not Your order is being processed look better than Order #9435893458358 is being processed?

The same applies to your weekly emails: You should not spend your time and place the word update or newsletter in the subject line. It has been proposed that these words may reduce your open rate. This language informs the readers that this email is not the first one and thus, they will be able to snatch the next one.

3. Use a Familiar Sender Name

 Email subject of the sender Susie Marino that includes the following statement: Will you be joining me today? Our recognition of the name above does not mean name recognition of the celebrities alone but rather of the familiar. Be as human as possible when defining your sender name. Olivia yourcompany.com sounds pleasant and friendly to individuals as they open their mailbox.

When you already know your recipients through a prior conversation, then when sending an email, you use your own name as the address of the sender, although technically, the company is the sender of the email. The best impression you could give your customers is that they are dealing with you, the person. Ultimately, people are busy. They do not even bother to find out whether you do not speak like a person and would be a comfy (or even pleasant) interlocutor.

4. Avoid the ‘No-Reply’ Sender Name

With the volume of spam received by people, most individuals are reluctant to open the mail of an unknown sender. And even fewer people want to talk to a robot. Imagine that you have to call a company and you are unable to reach a real person.

It’s frustrating, right? This is the same for email.

Do not use noreply company.com. It does not only appear less friendly, but it also prevents people to add your email to their address book. Rather, it is better to avoid a general email address and send the mail under the name of a real individual.

(Relayzo customers: Find out how to use customized “From” name and email address.)

5. Use Personalization Tokens

It is the personalization that we had referred to earlier. The fact that personalization tokens, such as name or location, are used in the subject line creates a sense of connection, particularly when it is a name.

No one does not like to hear his/her name. It also amplifies the click-through rate: The studies have established that those emails that included the first name of the recipient into the subject line received a better click-through percentage compared to those that did not.

The following is an example of an email that I received through the personal finance company Credit Karma. The email subject attracts me as it addresses me by my first name and informs me about a great offer to reduce my payment of car insurance.

The company can customize this email with the information that it holds about my car insurance payment, demographics, and location. Personalized email subject of the Credit Karma which states, Samantha, you can potentially reduce your car insurance payment.

The other tactic of personalization that can be used is to use subject lines that correspond to the location of the recipient – such as lists of the best outdoor bars and restaurants in their respective cities.

Small personal gestures are a sign that you do not only know the email address of your recipient. But without having the ability to (or feeling like) to use personalization tokens in the subject line, use you or your and you still get the impression that you are directly addressing them. In this case, just leave the personalization to excess. That can be a little creepy.

6. Segment Your Lists

Although email blasts that can be sent to the entire list may be pertinent and useful to some individuals, they will not be to others, and people will feel confused and frustrated. How come that this restaurant is sending me a list of the top local steakhouses since I am a vegetarian? Why are they sending me case studies at all since I had just joined its email list last night?

This is where segmentation is involved. Creating a personalized and preferences-based email list will boost the urge of your subscribers to open your email. Gartner discovered that half of consumers liked emails that communicate local or regional events and offers.

Individualize the experience with data on the activity of your customers: on which forms they have completed and on what industries they belong and what their personal preferences are.  List segmentation comes as a small trick in email marketing because you can customize the experience of those who receive your emails.

7. Use AI to Get Personal

The subject lines and the content of emails can be personalized by using AI tools. The use of AI in your subject lines might appear as adaptive testing. Adaptive testing determines differences in the traffic/open rates and automatically scales the traffic in such a way that those variations that perform better are displayed more and those that perform worse are scaled down.

Need some difficulty in devising variations? AI is good for that, too. A generative AI tool, such as HubSpot Campaign Assistant or an AI email writer, is able to generate dozens of ideas at the touch of a button.

Read this article about the way you can optimize your content through AI.

Conclusion

Writing high-performing subject lines is not just a creative exercise, it’s a core part of maximizing the benefits of email marketing. The right subject line can determine whether your message gets opened, ignored, or lost in the chaos of a busy inbox. By applying best practices like personalization, segmentation, familiar sender names, and AI-powered optimization, you can significantly improve your engagement rates.

Consistency also matters. The best email marketing service or tool is the one that helps you test, track, and optimize your subject lines with precision and this is exactly where Relayzo, a powerful self-hosted email marketing application, stands out. With full control over your infrastructure, deliverability, and audience data, Relayzo gives marketers the flexibility to experiment and fine-tune subject lines that resonate.

Lastly, don’t forget timing. Even the most well-crafted subject line will underperform if sent at the wrong moment. Understanding the best time to send marketing emails for your audience can dramatically boost your open and click-through rates.

By combining strong subject line best practices with the right tools and strategies, you set your campaigns up for consistent success and measurable growth. Let Relayzo help you get there.