I read an interesting article in the swedish magazine The Architect (Arkitekten) about creativity, written by Ann Lagerström. Here is a short quote:
"To be able to think outside the box, it's required that you break both your own and your brain's patterns and voluntarily induce both psychological and biological fear. Habits must be avoided, your mind's networks should be torn up, memories pushed aside, cells that previously knew who they usually talk to will be forced to become lost. And your insecure self (we are all basically insecure) must dare to show silly, naive, odd and inappropriate sides.
You got it. Creativity is not fun. It's deadly serious. Creativity equals anxiety."
She then points out of something very important: We must feel safe to dare all these things. In a safe environment without judgement, creativity sprouts. It's quite simple, but often overlooked. Especially in a professional creative environment, where you "kind of" know everyone involved, and teams are reorganized between projects. If you're lucky it works, but often it's just exceptionally uncreative.
I believe it's often a better idea to keep teams together that work well. The security you get from this is hard to beat. Changing team members constantly can of course spark some ideas, but striving for good combinations are probably more rewarding in the long run.
And a final advice from Ann Lagerström: Always split creative meetings in two, with a good night's sleep between them. That way you let your subconcious work on the problems during the night, and it's easier to keep the good ideas coming the next day. I'm sure that is a major reason why Google recommend their employees to take a nap in the middle of the day. And meditation gives the same benefits: Let everything go, restart your brain and find new perspectives.