Top 10 Email Marketing Must-Haves

8. Automated re-engagement: Be creative with subject lines to drive engagement from lapsed subscribers (i.e., those who haven't opened or clicked in more than six months, a year). This is also a good time to test a "make up or break up email," Pfeiffer said. It's a necessary part of list hygiene, and will make your list strong going forward by eliminating names that no longer want to hear from you.