Integrating google analytics in AEM

Well you can go through the following which coveres AEM integration with Google Analytic and Google Tag Manager

Link:- http://aemcorner.blogspot.in/2014/11/aem-integration-with-google-analytics.html

//Covering step by step to achieve the needful.

Another reference link that could come as some help is:-

Link:- http://trantorinc.com/integrating-adobe-experience-manager-with-google-tag-manager/

for best practices:

https://analytics.googleblog.com/ and https://3qdigital.com/analytics/get-started-with-google-analytics-best-practices-for-everyone/

Hope this helps

Regards,

Amit