Aida's four steps can still be applied to copy designed to drive interest, desire, and action - even if that action is not to make a purchase on the spot, but just to investigate further. Warning the radicati research group reported that the average person receives 92 business emails per day. The higher someone is in their organization, the more they tend to receive. Needless to say, that means it's far from easy to stand out from the hundreds of other emails most of us receive every day. As you might guess, the subject line of your email is key here. A voucher will open your email, giving you the opportunity to generate interest and desire.
A bad subject line renders the rest of your email useless. It doesn't matter how interesting or engaging you are if your email doesn't open in the first place. So what does a company mailing list good subject line look like? A good subject line sounds like it was written by a human. It doesn't seem automated; it doesn't try to trick recipients into opening the email ("Don't open this email" is a popular example of this tactic in action); and it does not create false expectations. While you can never be sure what someone will respond to best, subject lines that sound natural will work better on most prospects than subject lines that scream, "This is an email. Of sale". Another point worth considering when writing subject lines is how they will appear in your recipients' inboxes.
It would be nearly impossible to write a subject line that displays the way you want it to on all devices, for all email providers. However, at the very least, you should test how your subject line will appear in gmail, on typical desktop and mobile resolution. This is because only very short subject lines will display in full on a mobile device, while on desktop recipients will see the full subject line, in addition to part or all of the first email line. Things like this are often overlooked but can have a big impact on open rates. Along with all of this, you need to make sure you measure the effectiveness of subject lines with a kpi. In this context, it would most likely be the open rate.