Hear us now and thank us later; back up the databases and configurations prior to making a configuration change or applying an update.
Do not run your MIM service accounts in the enterprise admin, domain admin, schema admin, or account operator Active Directory groups.
Disable SharePoint indexing if you have deployed the MIM portal.
Try to keep the product up to date with the latest update as much as possible as the latest update fixes bugs and sometimes add new features and performance enhancements. Updates are found at http://bit.ly/MSFTIDMUpdates.
Also refer to the MIM 2016 Help
file for Best Practices and Microsoft's own best practices page at http://bit.ly/MIMMSFTBestPractices.