Instead of using the default admin account, create a new user and give them admin privileges, then disable both the default admin and any guest accounts.
Enable SMB 3 in the File Services control panel in DSM.
Hide the homes shared folder in “My Network Places” by setting the adforementioned option in the Shared Folder control panel in DSM. This is purely for aesthetic purposes.
Go through the Security control panel in DSM. (Check the control panel on a regular basis for new features.)
When creating folders, remember to set reasonable permissions.
Use rsync to transfer files. If using a different copying method, rsync’s dry-run mode with the c flag can be used to check everything has copied correctly.
Run the Security Advisor to see if anything else needs attention, and enable the regular scan schedule to perform a weekly scan.
Make sure daily backup stuff (S3, external hard-drive) is set up.
Git from the Package Center in DSM craps out whenever you tried to do anything via HTTPS. Fortunately, the solution is simple: download a recent CA Root certificate bundle to your DiskStation and point Git to it by setting http.sslCAinfo to the location of that file in your global or system-wide .gitignore.
Even with NTP synchronisation enabled in DSM’s Regional Options control panel the date and time will occasionally get out of sync. Creating a daily scheduled task to run the ntpdate -u -b [SOME-NTP-SERVER] command as root seems to keep things in check.
Daily and weekly scheduled tasks should be run at night.
Manually downloaded Python packages are regularly removed as part of some updates, so when reinstalling save time by keeping any source code in ~/src or any easily reachable folder.
When setting up DNS-O-Matic DDNS support in the External Access control panel, use all.dnsomatic.com for the hostname and replace any @ characters in the username with %30.
If using File Station‘s shared links functionality, ensure the Advanced tab in the External Access control panel is filled out so that correct URLs are generated.
Enable bad sector and disk lifespan warnings in Storage Manager.
The Task Scheduler control panel in DSM doesn’t tell you whether a task’s last run failed or succeeded. Running the command synoschedtask --get provides detailed information about tasks, including their last run statuses.
Extracting tar.gz files with tar: tar -zxvf [FILENAME] (I’m always forgetting the combination of flags).