User Profile Synchronization Service does not start

User Profile Sync Service is a must-have feature in SharePoint 2013 in order to look up AD users properly via the commonly used user lookup dialog or user lookup button.

While going through many installations and configurations projects of SharePoint, the User Profile Sync Service never started right the first time on me.  It does take extra steps to properly set up and configure.

Below is the common technique to resolve the issue.

1. Add service account user to SharePoint Farm Admin Group on SharePoint Server.
2. Add service account user to local admin group of the SharePoint Server.
3. Restart the Timer Service
4. Open ADSI Edit as domain admin.
1. Right-click and Connect To "Default naming context". 
2. Go to "Select a well known Naming context:" and choose "Configuration". 
3. Click [OK].
4. Expand Configuration. 
5. Right Click [CN=Configuration, DC....]. Select [Properties]. Select [Security].
6. Add service account user and assign [Read] and [Replicating Directory Changes] permissions.
7. Click [OK].
5. Now go to Central Admin Site.
6. Go to "Manage Service Applications"
7. Click [User Profile Service Application]. 
1. Check [Permissions] at the top ribbon menu. Make sure the service account user exists.
2. Check [Administrators] at the top ribbon menu.Make sure the service account user exists with full permission.
8. Try starting User Profile Sync Service again and see if it works.