How Subject Lines Can Boost Your Campaigns

Subject Lines

Subject lines are the single most important factor in email marketing campaigns because they are the factor that determines the fate of your email. Whether your message will be opened, deleted or flagged as spam relies solely on the quality of the subject line.

Because of that, there have been numerous attempts to unravel the winning combination in this regard. The simple conclusion is – there isn’t one. It’s up to every brand to come up with their unique style and tone of voice, and to stay consistent in the long run.

However, some practices are a definite no go, so let’s see what must and mustn’t be done.

Boost Mobile Experience

The majority of recipients are checking your offer on the go. The trend is predicted to rise in the future, so have a care. Optimize your messages and your subject lines so that they provide an optimum mobile experience.

How exactly is it done?

First of all, stay clear of large images, multiple fonts, inconvenient calls to action (small or unclear) and long subject lines. The optimum subject line length is around 41 characters, since this is the iPhone limit. The other most popular choice is Gmail, which displays up to 70 characters.

Test or send your message and check it on different devices and OSs, especially if you use emojis. They are displayed differently on different devices (if at all).

Announcing Discounts and Sales

It goes without saying that most popular offers include discounts and sales. In fact, 28% of subscribers subscribe to keep informed, while an additional 27% subscribe to save money. Your subject lines should reflect on the sentiment but also stay true to your brand’s communication style.

Brainstorming subject lines means knowing your audience. Without insights, even the finest of campaigns will fall short of expectations. Subject lines should resonate with the recipient and also inspire trust. It takes a while to build reputation, so don’t ruin it by sending random offers.

When sending retail emails, address the sense of urgency, offer a solution to a problem and trigger people’s curiosity. This is always the winning combination, regardless of the communication style. If you add a giveaway, you’ll triple your chances to attract new customers.

Here are some success story examples:


  1. Guess: Last chance to earn $100 to shop
  2. Rapha: Last chance to get 25% off all base layers
  3. IKEA: Save with this week’s flyer
  4. Guess: Don’t wait. You’ll miss out on the sale of the year.
  5. HP: Time is running out…Save up to $300


  1. Converse: Hundreds of new markdowns added today
  2. Pizza Hut: Feed your guests without breaking the bank
  3. La Mer: A little luxury at a great price
  4. Guess: You won’t believe who’s partnered with us
  5. Nissan: Your inside look at the all-new 2017 Nissan Armada

Problem Solving

  1. IKEA: Where do all these toys go?
  2. HP: Solve all your printing problems
  3. Sephora: Your beauty issues, solved
  4. Guess: Don’t wear last year’s styles.
  5. Rapha: Gift inspiration for the discerning cyclist


  1. Jersey Mike’s Subs: Enjoy a birthday gift on us (giveaway)
  2. Rapha: Complimentary gift wrap on all purchases
  3. Guess: Free shipping extended
  4. Sephora: 3 Days only – 10% off and free shipping
  5. Birchbox: Tell a friend. Get a month free.

Words to Use and Words to Avoid

Interestingly enough, there are plenty of tips on which keywords to use in subject lines, but not nearly enough has been said about the words to avoid. With the exception of spam-trigger words (the infamous CAN-SPAM Act), there’s almost no mention of them. Let’s rectify that.

On top of the obvious trigger words, some sentences simply stink of clickbaits. These include empty phrases, chat and call invitations, and unclear subject lines. It is essential that the subject line explains the offer directly, rather than be beating around the bush.

Examples of phrases to avoid include “quick question,” “join us for,” “you’re invited to,” “exclusive invitation to,” trying to connect” and similar.

As regards “positive” subject line keywords, these include “thank you,” “thanks,” “golden,” “bulletin,” “order today,” “breaking,” “introducing,” “orders over,” “off selected,” “alert,” “news,” “new,” “iPhone,” “available,” “latest,” “special,” “back in stock,” “sale starts,” “brand new” and “great deals,” “free delivery” and “available,” according to Adestra and Smart Insights.

Email marketing agency Alchemy Worx has come up with the following results: “upgrade,” “content,” “wonderful,” “just” and  “go” (top 5) followed by “promotional,” “voluntary,” “deduction,” “congratulations” and “snapshot.”


Everyone loves feeling special, and the same rule applies to email marketing. Personalized emails are a golden standard in marketing, but what about subject lines?

Some brands prefer sending personalized subject lines, as well as addressing people by their names in an attempt to make them feel that the offer is intended specially for them. Even the simplest of subject lines will work, as long as it addresses the recipient directly and announces the offer. Here’s an example from Pizza Hut: “Bob, try our new treat.” Short, concise and clear, but nonetheless effective for all that.

Personalization is, in fact, a process you should aim to establish from day one. Whenever a new customer subscribes for your newsletter, you should send them a personalized welcome message. You’d be surprised to learn how many brands miss out on this opportunity, even the biggest of them.

Another opportunity to boost personalization that is often overlooked is – cart reminders. These should feature a direct, short subject line reminding the customer about the unfinished purchase. It is also recommended to ask what went wrong (usually it’s a technical issue) as these two strategies combined will show the customer that you care.


Subject lines are – titles. When you see a poorly written title, do you read on?

The analogy is somewhat more complex when it comes to email marketing, as people are getting multiple offers and need to decide on the spot which ones to consider. Couple the tips mentioned above with the right timing. The best time to send emails is at 8 a.m. or 4 p.m. Stay focused, communicate clearly and don’t be afraid to ask for feedback. Polish this practice as you go, and great results are certain to follow.