How to get GUID of a SharePoint List or Document Library.

In Sharepoint , the easiest way to get GUID of List is:

1. Go to Sharepoint List or Library Setting
2. Click on Audience targeting settings 
3. Copy the url from the browser
4. You will get url something like this http://Sitename/subsites/_layouts/ListEnableTargeting.aspx?List={7a6d10fa-267c-468c-8d1e-1030323a5846}
5. From the url we only need text which is after ?List=
6. That text is GUID for the respective list