Maybe get them interested in some useful/simple automation/shortcuts stuff?
Bookmarklets? Easy to start.
I think the best option would be finding their uses/needs and tailoring the approach to that.
If they use excel/Libreoffice, maybe the Record macro option would be good? Or mail merge?
Teach them.about the quick access bar and some new shortcuts that would help them?
I think helping them with backing up settings and data would be a good thing too.
It'll be a good start, to get them to know the need and importance of backups. Backups could also make them more confident in trying out stuff. Like, knowing that they can come back to the backup if things go wrong.