Email Subject Lines Best Practices: The Complete List

Marketing campaigns and email newsletters survival in the inbox totally depends upon the way users scan and make an assessment of sender information and email subject line. It is the first impression and will either have a positive or a negative impact depending upon the subject line. It should give them a reason to open your email and read it. Moreover, your subject line must-

  • Generate curiosity and interest.
  • Match your main content to build credibility and trust.
  • Be brief, informative and comprehensive.
Email communication is inevitable for marketing any business. When you send an email to your clients or customers, the first thing to catch their sight is the email subject line. This decides the fate of your email, whether it is going to be read or it is heading straight to the trash.

An email subject line plays an important role in deciding the fate of an email in any email marketing campaign. As per a subject line study conducted by MailChimp, keeping subject lines simple and to the point proved to be the most dominant factor in the success of open rate of over 200 million emails.

So needless to say, you need to be very careful when you construct your email subject line. There are many do’s in this case, but it is more important to remember the don’ts. You need to know what should not go into your subject line that will make your customer run in the opposite direction i.e. either unsubscribe or straight away mark your email as 'SPAM'. Either way, it will badly hit your email marketing campaign.

Here's a list of 52 email subject line best practices to keep in mind that can make a powerful impact on your readers :

  1. Include localization: Including a city name in your email subject lines is better than a personalized message with a recipient's first or last name. Localization improves open rates.
  2. Use multiple subject lines: To start, you have to put on your thinking cap and get creative. Skim through the content of your email and use your intuition to determine the key message you’re communicating. Use this as the basis of your subject line.
  3. Keep subject lines short: The best email subject lines tend to be either really short (or really long). There’s a large correlation between the campaigns with the highest Open Rates being within 30-40 characters. Subject to the condition that these are bold, self-contained declarative statements. Get to the point quickly, and focus 100% on the major pain or benefit your campaign provides.
  4. Use promotional emails effectively: Promote contests and giveaways in your campaigns to reconnect with inactive subscribers. Send subscribers a poll or survey to find out what type of content they’re interested in.
  5. Ask a question: A question in your subject line inadvertently creates a call-to-action. Your recipients are more likely to open the email to get the answer, or simply gain a better understanding of why you’re asking.
  6. Focus on the negative implication: People want to protect themselves. So, focusing on the negative implications is one way to quickly grab someone’s attention and interest.
  7. Place your words strategically: Place the most important words at the beginning of your email subject line. This will allow you to catch your reader's attention and it makes more sense to put the most important information first.
  8. Provide step-by-step answers/guides: People need a deeper “How-To” to learn something new or just get better at what they are doing. These in-depth guides / processes grab immediate attention if it is directed to a pain area
  9. Use personalization tokens: We may never find a definite answer what is good and what is bad with regards to the personalized subject line. But, according to the Science of Email Marketing, emails that included the first name of the recipient in their subject line had higher clickthrough rates than emails that did not.
  10. Use vivid words that evoke emotion: The best subject lines are the ones which evoke an emotion. This emotion simply connects with your reader. The task is to find and get to the point with bold, powerful statements that instantly resonate with a person’s primal motivators and top-of-mind pain point.
  11. Don’t hyperbole anything: In short, do not make exaggerated statements or claims which are not meant to be taken literally.
  12. Business people expect business case: When you are trying to reach marketers, they expect a bit of professionalism and are more interested in case studies, whitepapers etc. The aim is to provide a trusted solution for resolving pain points. It need not be necessarily formal, should be communicated in a way that the reader (B2B marketer) sees the value in each mail you send.
  13. Customize subject lines: Customizing email subject lines will drive more attention to your emails. We understand that it's not possible to customize subject lines for each individual who receives your email, you can segment your audience into multiple groups so you can target each group or list separately.
  14. Test your email subject lines: Your email subject line is one of the single easiest elements to test in your email campaign. Tests can help you see how your email subject lines will look across devices, as well as how they compare to shorter or longer versions. Send test emails to see how subject lines render on all devices. This will help ensure that your subject line reads well wherever it’s sent.
  15. Create an A/B test campaign: It's all about figuring out what works best for your specific readers. Testing email subject line is critical to any email marketing campaign. You should constantly be A/B testing your subject lines and tweaking wording according to your results.
  16. Maintain subscribers' interest: An email subject line should be such that it makes your reader curious, so your reader cannot help himself and should open and read the email urgently. The success of your campaign depends on how well you maintain the interest of your subscribers over time.
  17. Don't make false promises: Don’t ever try to cheat your readers – so if you don’t want your subscribers to unsubscribe then never misinterpret your email content.
  18. Do tell them what's inside: It should be clear to your reader as what will they get out of this (make it beneficial for them ultimately). They must have an idea as to what does your email contain.
  19. Consider the from name (Company or Individual): The 'from name' can be as important as the subject line itself because subscribers won’t open emails from people they don’t recognize. Use the 'from name' strategically to say who you are as the sender, and keep it consistent over time.
  20. Use groups and segments for your list: Segmenting your readers into groups or lists helps you target better. Sending information that’s relevant to them becomes easy.
  21. Make sure it’s clear who your email is from: Use a familiar sender name .Most people hesitate to open email from unfamiliar senders, all thanks to a number of SPAM emails we receive these days. People are more likely to open an e-mail from someone they already consider an authority and an expert than someone they’ve never heard of.
  22. Time it right: Timing is everything – right? Well, it may not be everything, but it certainly matters, especially when it comes to getting subscribers to notice and open.
  23. Use concise language: Using the fewest possible words without sacrificing meaning makes your email subject lines more understandable. Focus on the core message in as few words as possible.
  24. Start with action-oriented verbs: Your subject lines inspire people to click. Including action verbs in your subject lines will be a lot more enticing, and your emails could be drastically more clickable.
  25. Make people feel special: The right phrasing can make your recipients feel special -- and the effect can be magical.
  26. Create a sense of urgency or include a deadline: Craft your subject lines to establish a personal connect and it can make your recipients feel special. Right phrasing can get the readers open your emails and the effect can be magical.
  27. Use numbers: Using data and numbers is an effective email marketing best practice. It is also a great way to get your emails noticed.
  28. Think of it like a title: As marketers, we typically put a lot of effort into writing compelling titles for blog posts, writing an email subject line that gets maximum open and click rate requires same efforts.
  29. Be visually different: In order to make your email stand out, you can try to make your subject line stand out visually: Consider using brackets, variations on capitalization, phone numbers, quotes, etc.
  30. Write clearly: People have short attention spans. So, don’t make them work too hard to understand your subject line. Use clear language and keep it short while cutting out any unnecessary words.
  31. Add a little pun (at times) to your subject lines: Who doesn't love pun? It's a great way to delight your recipients and spice up your emails. Just think about small ways you can slip a funny one-liner or a joke into your emails when it's appropriate. But don't overdo it.
  32. DON'T USE ALL CAPS: A subject line written in all CAPS going to get you an email open. Using all CAPS really rub people the wrong way. It is like yelling at people and people certainly don't like it.
  33. Exclamation points!!! : Overusing exclamation points in your subject lines may make your emails look spammy and people will certainly ignore them or will mark them as SPAM.
  34. Add preview text: We know that 'Preview text is not part of your email subject line, but it does appear next to it. So it certainly deserves your equal attention. Your subscribers will be able to read your first sentence or so without even opening your e-mail.
  35. Take out words that trigger SPAM filters: Avoid loud punctuation marks & symbols. Words like ‘free’, ‘guaranteed’ etc. won’t help you either. Don't use all CAPS and take out words that trigger spam filters.
  36. Try a teaser: Rather than giving away the punch line right at the start, give them a sneak peek into what your email has in for them. It's like a movie trailer intended to create interest before the movie releases.
  37. Command readers: A command is a direct call to action to encourage people to take some action. For example, Join Us, Download, Register etc.
  38. Compelling call to action: Use CTAs in your subject lines to provoke an immediate response from your readers. CTAs also create a sense of urgency and it can be a powerful tool for increasing open rates and user engagement.
  39. Add lists: Who doesn't like simplifying things? That's what lists do for us. Lists help break complicated concepts through a series of smaller parts.
  40. Make announcements: If you have anything exciting to share with your readers ( a news, an update, or an achievement), channel that into your subject line.
  41. Be unique: We just love unique things, don't we? A unique information for your customer is what your business can offer them that they can’t get anywhere else.
  42. Include something unexpected: Try include eyebrow-raising information into your email subject lines, which can be industry stats, little-known facts, or anything people aren’t used to hearing.
  43. Use of multimedia: Adding multimedia into your email content is definitely a good strategy to engage readers, but how would they know that your email contains an interesting video or a presentation? Tell them through your subject lines, so they don’t miss out.
  44. Don't always send out emails asking for help: Litmus indicates in their infographic that the fear of being scammed has made many consumers wary of emails that always ask for help or assistance.
  45. Don't always Include numbers: Now that everyone else is also using numbers in their email subject lines to attract more eyeballs, Don't use it too often. It may put your email in danger of getting lost in the abundance of “special offers” floating around in recipient's inbox.
  46. Eliminate filler words: Any words that don’t have a purpose or don’t help you accomplish the goal of your e-mail should simply be eliminated
  47. Avoid words that trigger spam filters: To know more about words that trigger spam filters, click here .
  48. Be human: Be conversational and write like a human being. In other words, don’t sound like a robot. Use language similar to what your target audience would use.
  49. Kick up excitement: Enthusiasm & excitement spreads, and it spreads quickly. If you’re excited about an upcoming event or an offer, your readers should feel the same. And your email subject line is the best way to communicate that excitement.
  50. Double-check everything: Make sure that your email subject lines are well-written and make sense. Ensure that everything is spelled correctly and there are no grammatical errors.
  51. Optimize for mobile: According to Litmus, nearly half of emails are being opened on smartphones and tablets – that’s a 500% increase in just four years. Mobile email apps display approximately 35 characters of a subject line in the inbox view. Anything more than that will be get cut off. To prior to optimizing your email subject line for Mobile devices, analyze how many of your emails get opened on smartphones and tablets.
  52. Use logical keywords for search and filtering: most people setup filters and folders to manage the clutter in their inbox. So it important to include related keywords in your subject lines to make email searchable.


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