You can send all the awesome emails you want—cool GIFs, great stories, funny memes—but none of it will matter if you don’t get your readers to open the emails. And a good way to ensure great open rates is to master the art of the subject line.
Sure, it’s only 50 characters, but a subject line is typically the thing that first grabs the attention of readers—or turns them off. Your subject lines should absolutely fit into your overall strategy, which means it’s easier to match their content to your goals.
Want to learn more about writing win-win subject lines? This graphic can help.
Source : https://www.marketingcloud.com/email-subject-line-best-practices/