Missing traffic

In reviewing Google Analytics for many posts, it appears that there is a large amount of traffic not being reported. Some pages show only one view when email campaigns indicate 100+ clicks to the page and I have spoken to several people who have the read the post. Any ideas on how to make full use of this plug in to get accurate reporting?

Thanks!

https://www.ads-software.com/extend/plugins/google-analytics-for-wordpress/