Email lists usually have an end-objective: to sell subscribers products or services.
What I notice with most email lists, even today, is the email sender is not focused on the right way to communicate with their readers.
Selling a product or service within an email is incredibly challenging. The better approach is to inform and help subscribers. Quickly. An email gets deleted within a few seconds, so the goal should be to get them to another piece of content and hook them in there.
This means providing education. This means giving information to help a subscriber on their life journey, whatever that journey is.
The email call-to-action button should focus on learning more, not selling more.
Landing page content is more likely to sell compared to an email. The email must get the reader to read more.
Instead of being wordy with emails, or sending dozens of emails to the same person in a month, try to fit the main content on one page or less of screen real estate in the email. Move the remaining content to a landing page, guide or informative course.
Consider where important information is laid out on mobile devices. If the call-to-action is near the bottom of the page, it might be missed on phones.
If I am subscribed to your email, you are likely very personalized with your approach. You cut to the chase and give me the information I need in a simple way.
Most email subscribers would prefer it this way.