7 Techniques for Writing Killer Subject Lines

Over 200 billion mails are sent every single day.

No, that was not a typo,  t-w-o—hundred—billion. You read it right the first time. Clearly, email continues to be the mainstay of sales/ marketing communication. Companies & sales teams rely heavily on email to capture the attention of prospects, educate audiences about products and services and nurture leads through the sales funnel.

With so many emails sent every day, everyone’s email inbox is inundated with tons of emails. So, now more than ever, it is imperative for B2B sales executives to craft emails that cut through the clutter. The first gatekeeper when it comes to writing powerful emails that convert is having a powerful subject line. It is often the single most important factor that determines whether your email gets read or not.

Think of your email subject line akin to a resume when it comes to a job search. The resume won’t land you a job but can get you an interview; likewise, the email subject line won’t get you a sale (yet) but will persuade your prospect to open the email so that it has a fighting chance of scoring a response.

So the main goal of the subject line is to get the prospect open your email. No more, no less. But with fewer than five seconds to convince a prospect to open an email instead of deleting it, how can we craft subject lines that have an edge?

Here are 7 techniques to write effective subject lines.


Simple subject lines need to be direct, succinct and straightforward. They convey the crux of the mail content in a crisp manner and a large number of your prospects will appreciate a little simplicity in their inbox from time to time. Here are some examples:

  • Sending You an Offer
  • An Idea for You
  • Mission Achieved
  • Goaaaaal!!

As a practice, it is recommended that you write your subject line after composing the email body and not the other way round. That way, you can read through your email and try to sum it down to a few crisp words.

Ask a queston

Not only do questions inspire the desire to answer, they can also be a way to wiggle yourself into your prospect’s shoes. By asking a question, you are engaging your prospect and that is what you want when you want to market something. For example, “Need a vacation?” will make the average overworked person think, “Yes!” and that feeling of “You know me and you get me” can translate to an opened email, which can translate to a prospect reading about your solution, which can translate to an increase in revenue for your company.

Few sample question subject lines are:

  • Too many leads to follow up?
  • Need more sales leads?
  • Losing sleep over legal compliance?
  • Taking too long to hire rockstar engineers?

Make it Personal

The subject line that screams, “yes, it’s about you…” to your prospect is one of the most powerful ways of getting them to open your email. A personalized email subject line would immediately hint your prospect that this is just not a template that has been floated around to tons of other people.

But personalization isn’t always about slapping a prospect’s name or their pet’s name in the subject line. That’s fine, but there are several ways to personalize a message. For example, you can personalize around geography by talking about events, ideas, conferences etc., that are taking place in the prospect’s local area. That being said, the eCommerce world has gotten awfully tricky at using remarketing practices to target emails based on their customers’ recent searches and/or purchases, which is another form of effective personalization. Some good examples are:

  • Janice Morgan, your next trip is on us
  • A Stock Portfolio for Justin Carver
  • Bernie Madoff, Happy with your Stockbroker?
  • Coming to Dreamforce? Drop by our stall

be funny

A humorous subject line can really stand out among the mundane and dull emails surrounding it. But humor is very subjective, it thrives on exclusivity, which isn’t always great if you’re trying to appeal to the masses. However, if you know your audience well and your emails are targeted, a well-placed humor can get your email opened and can earn major reputation points with folks on your wavelength. Some funny email subject line examples:

  • There are no deals in this email (Groupon)
  • Impress Your Cranky CEO
  • We Like Being Used (The Muse)
  • Papa’s in the House (a Papa John’s email promoting an offer)


Arousing your prospect’s curiosity by delivering an intriguing subject line can motivate your prospect to open an email. Using a curious subject line always helps as it catches attention and piques the interest of your prospects without giving away too much information, leading to higher opens. Be careful though, as curiosity-based subject lines can get old fast and are the most likely to miss their mark if you do not fulfill the reader’s expectations with information that at least partially satisfies his curiosity. Here are a few intriguing promise subject line templates:

  • Here is a way to crush your top competitor
  • Hidden Truths: 17 Ways to Get More Leads
  • Marketing Secrets that your Competitors Don’t Want You to Know
  • Your Customers are waiting


Using urgency in the subject line is a time-honored method of creating anxiety. Most of us have a deep, inherent terror of being left behind, of missing out – that flock mentality was a survival instinct once, but now it’s another subject line strategy to goad the prospect into a purchase. Many people respond better to the threat of losing than to the promise of gaining so this can be a powerful email subject line technique if applied correctly.

Creating a sense of urgency doesn’t just mean adding an “!” after a generic statement. However, time-sensitive offers, releases, pre-releases, launches, etc., can be a very effective means of getting your readers to respond and take action. But this isn’t the subject line technique you want to use all the time (remember the Boy Who Cried Wolf), but it is very effective when it makes sense.

  • Only 3 weeks left to crush this quarter’s targets
  • 5 Slots Left in this Webinar
  • Last chance to grab this offer


Numbers and lists are one of the most prolific techniques used for subject lines and blog posts because they are extremely effective. For those of us who want to write a good subject line, it is hard to believe that they still generate interest, but believe me, they certainly do. Incorporating numbers into your subject line attracts attention, as our brains are naturally drawn to digits. This tends to be why top 10 lists are so successful – lists are easier for our brains to process and they create curiosity, in addition to providing the promise of a quick and easy read. Perhaps, if nothing else, the reader knows they are going to open something that has been written in an organized fashion. Few examples are:

  • 5 Steps to turn around your SEO
  • 3 Ways we can help you
  • 4 Reasons Why You Need to Use A Sales Emailer
  • 3 Ways to improve your page loading speed

The Bottom line:

There are many ways to write an interesting, compelling subject line based on these techniques that we have focused on. But remember that there isn’t a one-size-fits-all answer to crafting the best email subject line. The best thumb rule to use when writing a subject line is to put yourself in the shoes of your recipients. Consider which types of subject lines would turn you away, and avoid using them. Make it your goal to engage your recipients with clear subject lines that communicate that the valuable information they seek is a mere click away. Giving value is the simple way to achieve the highest open and click-through rates.

Few general good email subject line best practices to keep in mind when crafting your subject lines:

  1. Write multiple subject lines. Try subject lines for every email and then choose the best.
  2. Keep it under 50 characters. Imposing a 50 character limit forces you to trim unnecessary words and make it crisp
  3. Know your audience. Pay attention to what they like. Your best bet for creating good email subject lines will be understanding your audience intimately and catering to their likes.
  4. Choose your tone. Most good email subject lines rely on a conversational and casual tone to attract an audience. Take time to think about what tone do you wish to convey
  5. Be Honest.  Users want to see that you are a legitimate and trusted source. Your email body needs to deliver on any promises you make in your subject line.
  6. Test, test, test. The best way to find what works for your audience is to A/B test your email subject lines. While it can be tempting to use your intuition to predict what subject line language will make people click on your emails, you should constantly be A/B testing your subject lines and tweaking wording according to your results. What works best for your audience: Long or short subject lines? Including numbers or not including numbers? Questions or statements?

What other tips and techniques have you used for improving your email subject lines? Share with us in the comments section.

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