Restart your Mac
Empty the Trash
Delete Time Machine local snapshots
Remove old iPhone and iPad backups
Clear application caches
Remove large log files
Delete old installer files
Remove unused disk images
Clear browser cache
Delete Mail downloads and attachments
Remove Messages attachments
Uninstall unused apps
Delete old Xcode derived data and simulators
Clear system and user temporary files
Reduce Time Machine backup size
Update macOS
Use Storage Management to review and delete large files
Use a trusted Mac cleaning tool if needed