Your better fascist states typically have a loudspeaker system projecting propaganda in public places and making announcements on high. I'm not sure if Magic Mouth is still around, but you could have permanent magic mouths repeating, "The leader is your friend. Obey the leader!" or "The spies of the Enemy are everywhere! Suspect everyone! Trust only the leader!" Write up a list of a few dozen such commands. Sprinkle as necessary for flavor. (Heck, no need for permanency if you've got the manpower. You just need dedicated spell-casters to do it every day.)
Target the charm persons on the friends and families of suspected subversives to foster informing and collaboration. Too expensive to just cast it on everyone. (Although, you could taint the water supply with a "charm person" potion, I guess. It's not that different from a love potion.)
Finally, a good use for familiars. See previous parts of this thread for material on animal spies.
Public use of properly worded suggestion and command spells might have a great impact. ("Confess!" "Turn yourself in to the proper authorities!" "State the name of the leader of the resistance movement." "Sign up for Gnome Youth groups now!")
Some fascist societies have an obsession with order and hygenics. Make sure to have the streets prestidigitation'ed every couple of hours.
Might want to watch The Prisoner for inspiration on diabolical techniques, but since they tended to like truth serums and hallucinogens a lot, not every episode will be helpful. See above re: water supply and potions.
Skills: Now is the time to really abuse the social skills of diplomacy, bluff, intimidation, gather information, sense motive, craft:writing and perform. Yes, perform and craft:writing! The Italian Facists crafted a "Cinema of Distraction" to keep the populace fat and happy. Need I remind you about the power of Nazi rhetoric and Riefenstahl's films? Now let's talk about what a few dozen evil expert writers might be able to do to the impressionable minds of young children. Evil school textbooks! Or, you'll recall what Orwell did with government book publishing in his book, 1984. Go read the threads where people argue that these skills are broken and see what you can LEGITIMATELY use. Have npcs go, "You know, now that you put it that way, it does make a lot of sense! The leader really is my friend! Gnomes should be trusted. Elves really are the skum of the earth!"
For total creep factor: the Dream and Nightmare spells. The leader is talking to you in your dreams! Randomize in the populace every week or so to save on expenses.
Fake terrorist incidents. Have concealed summoners use stilled, silent spells to bring in something nasty every once in a while, so that the City Guard can instill order and provide the "national emergency" excuse for all these decreases in civil liberties.
Instill an hysterical fear of the Other far beyond the actual threat they pose.