It is hard to over state how important a subject line is to the success of your permission-based email marketing campaigns and email newsletters. First, the subject line is the first writing that the recipients see and is often the determining factor on whether the recipient opens the email or moves on to something else. Second, doing this well can mean the difference between your emails arriving in the Inbox and not the junk folder.
At base, the subject should achieve something fairly simple: It should set proper expectation as to what to expect in the body of the email.
Elements of a Bad Subject Line
A bad subject line is sort of like the proverbial old school, high-pressure salesman in a polyester suit. He made inflated claims and wanted you to sign on the dotted line right now before it was too late to take advantage of a once in a lifetime opportunity. Fortunately, this species is much more rare these days.
The good, modern salesperson is knowledgeable, conversational, persistent, and honest about the product. The good, modern salesperson does not speak the language of hype but talks to the prospect or repeat customer as though they were having a cup of coffee together.
Avoid ALL CAPITAL LETTERS as that is widely thought of as the Internet equivalent of shouting. You would never shout at a prospect so do not shout at your email list subscribers. Avoid exclamation marks!! When I see exclamation marks I think of Mr. Polyester hype-talking his way out of sale. It is worth noting that if it looks like hype to you, the spam filters probably agree. For example, the filters are likely to flag emails that have ALL CAPS or exclamation marks and send them to the junk folder.
A good litmus test is does it past the read test? If you read it out loud does it sound even vaguely how you would talk to the customer over coffee?
Elements of a Good Subject Line
As mentioned earlier, set proper expectations regarding the subject of the email. A good subject line communicates clearly the subject of the email. Most good subject lines are straightforward, clear, and do not cram in too much stuff. Many good subject lines are fairly simple.
This does not mean you cannot use the subject line to sell, as you definitely can. Here is an example I recently got from from one of my favorite online publications:
From: MarketingProfs Events
Subject: Early Bird Ends Friday: Grab Your Discount
First, notice that they branded the From address so I recognized the source instantly. This made up for the non-branded subject line. Second, notice the sense of urgency and anticipation. There is some sort of event by a company I like and I can get a better deal if I act by Friday.
The copy writing in the email supports the subject line very well with a description of the event, some humor, and a strong call to action with links to a good landing page.
It is worth noting that everything from the subject line to the copy writing in the email was compelling while being slightly understated. This slightly understated tone takes away the feeling of high pressure, while still maintaining a sense of urgency. Well played.