Here are some useful links to help you avoid making these common mistakes with Active Directory...
Most Common Mistakes in Active Directory and Domain Services – Part 1 – MEA SI Blog
https://blogs.technet.microsoft.com/meamcs/2018/12/31/most-common-mistakes-in-active-directory-and-d...
Most Common Mistakes in Active Directory and Domain Services – Part 2 – MEA SI Blog
https://blogs.technet.microsoft.com/meamcs/2019/01/08/most-common-mistakes-in-active-directory-and-d...
