When you send cold emails to your prospects, you are competing with dozens of emails in their inbox. Just imagine—there were around 300 billion emails sent in 2019. The average professional receives 126 emails per day. That’s a lot of competition! For your cold email campaign, the primary goal should be to stand out from the crowd and make prospects open your emails. Subject lines are undoubtedly the most crucial factor when it comes to whether your emails are going to be read or not. In this guide, we gathered the most effective tips on how to craft a perfect cold email subject line and make people open your cold emails. We collected some of the best-performing cold email subject lines we tested and asked industry experts to share their best practices.