Writing & Editing How to write irresistible e-mail subject lines The five tips you need to know to ensure people open your e-mails. By Matthew Royse@mattroyseFeb. 9, 2011 SHARE The marketing firm Knotice compiled a list of five tips to make those subject lines irresistible. Here’s one: To read the full story, log in. Become a Ragan Insider member to read this article and all other archived content. Sign up today Already a member? Log in here. Learn more about Ragan Insider.