30% OFF on yearly plans. Limited time offer. coupon: WOOHOO

7 Email Subject Lines Hacks to Boost Open Rates and Conversions

Email Subject Lines Hacks

Did you know that sender’s name and subject line are two of the most important factors that determine the opening rate of an email marketing campaign? Well, writing a captivating subject line is a sure way to compel your recipient to open your email and then engage with your email to achieve the results you desire by sending the email.

A subject line is a quick and short way to grab your recipient’s attention within a few seconds. That is why you need to put in much effort to make sure your email subject line leaves an impactful first impression whenever your email is received.

And, in this post, we will share with you all the tips to help you write a compelling subject line.

1. Trigger The Recipient’s FOMO

For those of you that might not know what FOMO is, FOMO stands for Fear Of Missing Out. And triggering a recipient’s FOMO simply means creating some sense of urgency. And, by doing this, you will make the recipient feel as though they are being left out of a fleeting deal or a fleeting piece of information, which will trigger them to act urgently. Many marketers use this trick to make recipients feel anxious and curious.

So, now, the question is: how do you create this FOMO?

It is simple; you want to make sure your subject line highlights a discount, sale, or event your company is running. So, for example, assuming your company sells jewelry, you can write your subject line as “This is your last chance to grab your favorite jewelry at a 30% discount.” Or, if it is an event your company is hosting, you can write something like this “Be part of the first 50 people to be admitted to our event for free.” Writing subject lines like these automatically makes the person feel like they will be left out of something special if they do not take instant action.

Here is a detailed guide to help you create FOMO in your email campaigns. It is important to note that you cannot use FOMO in every email campaign, remember only to use FOMO when you are offering a sale and hosting an event.

2. Personalize Your Subject Lines

Many email marketers make common mistakes in sending generic emails out to their email recipients and expecting them to work. Even though sending out an email with a generic subject line might work, personalizing your emails subject lines will increase the open rate of your email marketing campaign by 26%.

By personalizing your subject line, I mean simply adding the recipient’s name to the email. And doing this can be powerful if combined with any of the tips we discuss in this article. For example, instead of just writing, “This is your last chance to grab some jewelry at a 30% discount.” You can also write, “Conor, this is your last chance to grab some jewelry at a 30% discount”.

We all love it when someone calls us by our name, so, doing this, you make the recipient feel special because they feel like the email was actually intended for them, and just not for everyone. So, they are more likely to open your email.

3. Trigger Their Curiosity

Yes, another way to make sure you write a compelling subject is to trigger the recipient’s curiosity. It means you want to provide the user with the insight they do not know about. This can be achieved by asking a question with statistics they do not know about– a typical example is how we wrote the intro of this article. Alternatively, you can go straight to the point and provide your recipients with some tips.

You want to make sure your subject line grabs the recipient’s attention by leaving a loop in the subject line that triggers the user’s curiosity to open your email. Also, you want to ensure that you satisfy their curiosity in the body of the email to avoid click-baiting, and then make sure that the recipient anticipates your email next time.

Some examples of subject lines that can trigger the recipient’s curiosity include: “Did you call us?” With this, the recipient will wonder if they really called you, and then they will be intrigued to find out what you have to say. Another example is “You have been doing your marketing all wrong” This will make the recipient curious as to how what it is they are doing wrong.

Well, according to Professor George Loewenstein, there are five ways to trigger the curiosity of someone. These include:

  • Asking questions
  • Unfinished stories
  • Making controversial or unexpected statements
  • Make the person feel as though you have a piece of information they do not have
  • Make the person feel as if they have certain info they have forgotten.

Details of utilizing these steps are highlighted in his book: The Psychology Of Curiosity: A Review and Reinterpretation.

So, you want to make sure that you integrate and leverage two or more of these factors when writing your email subject line to make sure that you grab the attention of the recipient immediately.

4. Try A/B Split Testing

Split testing is something many small businesses do not do because most people feel it is time-consuming. However, if you can split test your subject lines, you can easily detect what subject line works and what subject line doesn’t work. What split testing means is that you are deploying two or more sets of emails with different subject lines to your recipients. The aim is to easily detect the most effective subject line or email marketing campaign based on opening or conversion rates.

You can never determine the effectiveness of one subject over the other without actually testing them. So, you want to come up with a list of 3 to 5 subject lines you want to try and then leverage the A/B split testing feature to what subject line works.

This makes A/B split testing one of the most effective ways to easily test and compare two or more subject lines among two groups of people to see which of the subject lines performed better than the other. The results gotten from the split test makes it easy for you to know how to tweak the other subject line that didn’t perform well to make it more compelling.

Most email marketing software enables you to perform A/B split testing easily, so it shouldn’t be a problem. If you are looking to purchase your first email marketing software, this list should provide you with software that offers a/b split testing.

In addition, to split testing, you want to make sure that you segment your recipients. This is because each person is different, and each of your prospects will react differently to certain subject lines than others. And by segmenting your audience, you can send relevant emails with highly-targeted subject lines to the audience. Therefore, you can send specific subject lines to specific segments based on their behavioral pattern by segmenting your audience.

5. Keep Them Under 10 Words

You want to make sure that your email subject line is so straightforward, and there is no better way to do this than to keep your subject line under ten words. Keeping your subject line short makes it easy for your recipient to read the subject line within a glance. By this glance, the recipient can decide whether they will open your email or not.

Also, keeping them under ten words makes it possible for the whole subject line to appear on smartphones and smartwatches. Most people tend to use their phones to check emails. Therefore, you want to ensure that your subject line fully appears on the phone or smartwatch screen and isn’t truncated because it is too long. Even applications like Outlook and Gmail give the recipient a little preview of the subject line; therefore, you want to ensure that your entire subject line is captured in that little preview without getting cut off.

Also, some studies have been able to correlate the open rate of an email marketing campaign to the length of a subject line. It was shown that the shorter your subject line is (under 70 characters), the higher your opening rate.

6. Avoid Sales Lingua

Yes, we know you are trying to get your recipients to take a certain action to benefit your business. However, you will need to slow down a bit and do not come off as a salesperson. This is because it creates an impression that you just want to take from them. To avoid this, you want to make sure that your subject line communicates value to the recipient. You want it to seem as though you are giving to the recipient rather than taking from them.

A great way to discover this is to put yourself in the recipient’s shoes and then try to figure out what value you can provide them. Generally, you want your subject line to seem as though you are offering the recipient something. So, for example, instead of writing “Come and purchase my software,” you can write, “Conor, we are offering you $50 off your purchase of my software.” With this example, the value provided is that you have the recipient save money by offering them a discount. 

So, assuming you are a real estate company, one of the ways you can write your subject lines can be: “Hey Conor, here are five ways to finance your mortgage with low-interest rates.” Then, later on in the body of the email, you can then sell your product or service to the recipient. To enhance your outreach, consider attaching examples of success stories or real estate brochure samples that highlight the benefits of your services.

7. Send Them At The Right Time

Finally, you want to make sure that you deploy your emails at an ideal time the recipient is most likely to open your message. You want to make sure that your email should be on the top 10 list when the recipient opens their email provider. This is important because the average person receives 121 business emails each day. So, if you do not send the email at an ideal time when the prospect is most likely to read your email, you risk the chances of having your email being pushed to the bottom.

This can be a great disadvantage because no matter how precise and intriguing your email subject line is, if it doesn’t appear on the first page of the recipient email, then there is a higher chance that your email might be skipped. And this can be a waste of time. Therefore you should make sure that you send your emails with the best subject lines between 6 am and 10 am. This is because during these periods, people have started their day, and the first thing they will open before working out, or while eating some cereal, or before actually starting work is their email. Also, you want to send them between 6 pm to 9 pm. This is because most people have just ended their day, and they are just relaxing, and they will check their emails before going to bed or while on the way home.

So, to ensure that you do not waste your time writing catchy subject lines and email campaigns that wouldn’t get read, you want to make sure that you send the emails at appropriate times.

Bonus Tip: Avoid Spams

The last thing you want is to waste your time composing an email and a subject line only for it to end up in the recipient’s spam box. As you already know, the spam box is the least visited section of an email. Therefore, you want to make sure that you put in all the effort to prevent your emails campaigns from ending in the spam box.

The truth is that each day, these spam rules become tighter, and this increases the chance of having your email moved to the spam box or junk folder. However, here are a few tips to prevent that.

  • Ensure that the people you are emailing willingly subscribe to your email list. Do not buy email contacts and start sending emails to them.
  • Avoid using spam keywords.
  • Always give them an option to opt-out of your email list.
  • Check your IP and make sure it isn’t blacklisted.
  • Do not send spammy emails.


Subject lines are compelling because they are the deciding factor that determines whether someone opens your email or not. Therefore, you want to make sure that you sit down with your team or yourself and thing brainstorm on the most compelling subject line that suits the audience you serve.

Join 68,000+ marketers today

Get exclusive updates, invites and tips from our team of marketing experts.

Join more than 80,000 brands using Woorise

Easily create landing pages, forms, surveys, quizzes & viral giveaways that drive real user engagement.