I would use Cash. Great motivator.
Failing that, I would stay way and truly away from threats/violence.
"Yes, the lightning bolt spell always ends with your thumbs pointing inwards, but you cant cast it just yet, you need a level or two more. Practice at home. Bye bye"
In SUC there is an arcane list - Devious ways. The level 8 spell - Influence would do what you need, but if you can get that list you probably dont have that many problems with normal lists...