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Email Marketing Subject Line Best Practices

This guide covers the dos and don’ts for writing email subject lines that help your messages reach the inbox and get opened.

Key Tips for Writing Subject Lines:

Do:

  • Add personalization: Use the recipient’s first name to boost open rates. If testing, provide the first names of your seed list.

  • Be descriptive: Clearly state the benefit or offer. Avoid vague or overly trendy phrases like “Fall into savings.”

  • Keep it short: Aim for 9 words or fewer and under 60 characters to ensure it shows well, especially on mobile devices.

  • Limit punctuation: Use no more than 3 punctuation marks to avoid looking like spam.

  • Use emojis sparingly: Include only 1 emoji per subject line and use it to support your message, not replace words.

  • Mention promotions: Highlight sales or special offers to entice recipients to open your email.


Don’t:

  • Put spaces between letters in words (e.g., “S A L E”)

  • Use subject lines longer than 50 characters (20-40 is ideal)

  • Write in ALL CAPS

  • Overuse punctuation marks (e.g., “!!!”)

  • Make spelling or grammar mistakes

  • Beg or plead for opens (“Read me!”)

  • Reveal everything in the subject line

  • Use one-word subject lines

  • Repeat the same words too often in subject and body

  • Add “re:” or “fw:” to trick readers

  • Make false promises

  • Use the word “Help” (it’s often ignored)


Examples of Successful Subject Lines:

  • Your Daily Horoscope and Local Weather 11 December 2021

  • Jenna, Jump Start the Holidays at Colonial Kia

  • Cyber Monday Daily Deals All Week

  • Cyber Week starts early – shop amazing savings

  • Treat Your Tastebuds to Lobster Night

  • Save Big with the blu PLUS+ Xpress Bundle

  • See our brand new Cadillac specials


Words to Avoid (to prevent spam filters):

Avoid words and phrases like:
!!!, #1, $$$, 100% free, Act Now!, Buy direct, Cheap, Click Here, Discount, Free gift, Guarantee, Limited time offer, Make $, No obligation, Order Now, Save $, Urgent, Win, and many more.