Exit Intent Popup
Try showing a popup on exit or after a specific amount of time on page to get emails. If your blog or website is getting a lot of visitors, but not generating a lot of emails, you should offer readers the opportunity to engage more fully with your content before they leave the page. A Wordstream case study showed that using an exit popup reduced bounce rate by over 60% and increased time on page by over 50%. SumoMe has a great tool that makes building your exit popup easy.
https://sumome.com/app/list-builder
http://searchengineland.com/reducing-site-bounce-rate-bounce-exchange-review-186968