Rip their clothes off. Creative people always have something up their sleeves. That's why they wear loose shirts. Find those anticipated award, raises, promotions, and expose them. Of course, if you can, you want to nip creative initiative in the bud, before it bites you in the butt.
Shower creatives with phony promotions.
Constant lip service works, too. Don't forget to regulate. A word of warning. You can stifle creativity, but you can't kill it. No matter how hard you try.