Tip 19. Use proper subject lines
When you write an e-mail, always check that you’ve entered an appropriate description in the “subject” field.
Describe fully and precisely the subject of every e-mail you send. This will help you to quickly find the e-mail later. It will also help the person you e-mailed to manage their inbox, which will in turn help them to give your messages the appropriate attention. Do not leave the subject field blank and do not use vague descriptions such as “Hello” or “Letter” or “Agreement”. Spammers often use those headers and a spam filter blocks such e-mails.