I've long been a fan of the "sleep on it" technique, because it usually works. Whether our unconscious brain solves the problem while we sleep, or the rest and distance lower our stress level to free the blockage is up for debate. Regardless, you can't rush creativity. Like cooking, it takes time. And turning up the heat rarely delivers a better meal.
Of additional interest is the finding that the cerebellum, the brain region typically associated with movement, is involved in creativity.