Open and click-through rates (CTRs): Knowing who are engaged customers (those who open most emails and end up making purchases) versus inactive customers (who haven’t opened any emails in months) can be invaluable. Marketing campaigns announcing a new product should absolutely include those engaged customers, while re-engagement campaigns can be created to try and entice the inactive customers.
Be clear about what people can get and how to get it. This is the backbone of this email marketing strategy. Tell people about the benefits they can get. Write a separate email about each major benefit, if you want. Make sure those benefits come out clearly. But also keep it conversational. Don’t just list a bunch of benefits and expect people to buy. Also, remember to be clear about what they need to do to get those benefits. Tell them to “click here” or “apply for a consultation.” Don’t force people to think about how to move forward. It’s not that they couldn’t figure it out. It’s just unnecessary (and therefor annoying) when you could make it easy for them.
Emails triggered by milestones, like anniversaries and birthdays, are fun to get -- who doesn't like to celebrate a special occasion? The beauty of anniversary emails, in particular, is that they don't require subscribers to input any extra data, and they can work for a variety of senders. Plus, the timeframe can be modified based on the business model.
Everyone's busy and their inbox is already full. Why add to the problem with a longwinded email? People generally like short, concise emails better than long ones because concise emails have an obvious focus. Plus, when your users are scanning through all their emails in a short amount of time, they're more likely to find the overall message before deciding to take any action.