Hi Kedler,
When have cloning of PRD over DEV/TEST done we do have below checked.
1. Get XML backup of uncommitted update sets.
2. Disable outbound Email routing/route it to TEST mailbox (depends on your org)
3. Change Themes for cloned instance (DEV/TEST)
4. Grant Necessary testers impersonation/approvals roles
5. We also follow monthly releases & make sure we get atleast DEV cloned after a week from Release in PRD which helps to keep instances in sync with PRD & also act as a source to work on/look for development activity that may have failed when pushed to PRD.
In addition you may refer below links for Clone best practices.
Video blog
Wiki
Thanks,
Jaspal Singh
Hit Helpful or Correct on the impact of response.
Some pointers:
1) From a data security point of view, the best process is to exclude the tables that you know will contain sensitive information. More information on excluding tables, here:
https://docs.servicenow.com/bundle/kingston-platform-administration/page/administer/managing-data/task/t_ExcludeATableFromCloning.html
If you want data for testing purposes then take an xml backup of the excluded table from the sub prod instances.
2) If you need selective data then the only option is to clean up the data post clone.
https://docs.servicenow.com/bundle/kingston-platform-administration/page/administer/managing-data/concept/post-clone-cleanup-scripts.html
3) for system files, you can use preservers
https://docs.servicenow.com/bundle/kingston-platform-administration/page/administer/managing-data/concept/post-clone-cleanup-scripts.html