Add personalization

Use merge tags to personalize your subject lines with each recipient's name or location. Personalization is shown to increase open rates for most users, and may work well when combined with targeted automations such as birthday deals and post-purchase follow-ups.

Be descriptive

Sometimes, it's better to be direct and descriptive than trendy. Seasonal slogans such as "Fall into savings" or "Sizzling summer bargains" are popular but don't offer a specific hook. Instead, try to communicate the benefits of your promotions, or call attention to specific deals.

Keep it short

For many recipients, especially those reading your emails on mobile devices, shorter is often better. We recommend you use no more than 9 words and 60 characters.

Limit punctuation

Research shows that it’s best to use no more than 3 punctuation marks per subject line. Too many punctuation marks can make your email look like spam, especially if you use a lot of special characters.

Use emojis carefully

MailChimp offers a built-in emoji picker is a fun and easy way to add some visual pizazz to your subject lines. However, there are a few things to keep in mind when you use emojis.

• According to research, you should use no more than 1 emoji at a time.
• Use emojis to supplement words rather than replace them, to make sure your main message gets across.
• Different operating systems render different versions of emojis, so it’s important to test.

Test subject lines

There are a few ways to learn whether your subject line is a likely winner: MailChimp offers a built-in subject line helper, view your recent subject line performance, or use an A/B test or Multivariate test to see if different subject lines affect your open rates.

*this content came from MailChimp