Keep email subject lines short (under 50 characters) and descriptive to entice readers to open the email. Send emails at night between 8-12pm when open rates are highest. Design emails to be readable on mobile by using a single column layout and larger fonts. Re-engage inactive subscribers by segmenting them and sending targeted reconnection emails. Use surveys to learn more about subscribers and tailor future messaging. Include free content like ebooks to incentivize opens and clicks.