The trick is not not try and force creativity because it's actually more dependent upon a relaxed state of mind.....it works a bit like one of those skeet shooting games with a light gun where if you concentrate you don't hit shit but if you kind of zone out and stare at the screen you can hit everything, you know it's like that "too many minds" scene in the Last Samurai where he keeps getting hit until he learns to zone out and relax so he can focus instinctively......well that's how it works with creativity too, if you relax your mind it should flow naturally.