Sending mails to users is not as difficult as getting this mails opened. There are many recipients that have refused to open their mails even when the mails have been sent a long time ago. How will a mail marketer ensure that recipients open their mails?

Use the appropriate emojis especially for those that don't like reading long mails. Mail marketers can as well ask for feedback to ensure that there is continuity of exchange of messages.

What are else do you think?