You’ve heard the expression, the money’s in the list. Successful online marketers will testify to the truth of this statement, but before you can earn an income from your list of email subscribers, you will need to build a trusting relationship with them. That relationship cannot really begin unless they open your emails. For your email marketing messages to be opened, the email subject lines you use have to command attention in the same way that attractive newspaper headlines get people to read newspapers.
This article by Brian Clark, on the CopyBlogger site, gives three useful tips to use when crafting good email subject lines which will ensure you have the best chance of having your emails opened.