Writing a useful email subject line
A subject line should help someone decide whether to open now, save for later, or ignore. Name the change, deadline, or topic plainly. The preview text can add a useful detail rather than repeat the subject.
Avoid urgency that the message cannot support. If the email is about an account change, put the action and timing in both the subject and the body.
Test a few options against the actual message. A high open rate does not help if the reader expected something else.
