Write a compelling subject line. The subject of your email will be the first thing that people will see when viewing it. Because of the immense amount of spam that exists, it's important that you draw the recipient in enough so that they open the message. The subject line should invite the reader to some benefit or include a sense of urgency which requires action. Avoid cliche marketing terminology like "act now" or "free limited offer" as these subject lines can make recipients feel suspicious and turned off. Your subject line should be 50 characters or less.
The downside of just making offers is that they’re not useful on their own. People on your list won’t receive any value from you unless they buy what you’re promoting, so they have little reason to stay subscribed. That’s why this email marketing strategy doesn’t work alone. And it’s why many e-commerce sites struggle to keep people interested. There are a few exceptions (e.g., Groupon) that rely entirely on making offers—but then the reason people joined the list was specifically to receive those offers.
Marketing emails need to be personalized to the reader and filled with interesting graphics. Few people want to read emails that are addressed "Dear Sir/Madam" -- as opposed to their first or last name -- and even fewer people want to read an email that simply gives them a wall of text. Visuals help your recipients quickly understand what the point of the email is.
Sample review: “See what happens to your emails after you press send…you’ll know exactly when they opened your email and whether or not they clicked on your link. BananaTag will even tell you whether they’re on their desktop or mobile device. And best of all, your email appears NO different to your contacts. All of the tracking is done seamlessly without any change in the user experience.” — BuzzBlogger