Have you created previous games with the same company? If you have I would try to keep a little of the same style so that you know it`s your company that would of made that particular game. If you have a good idea as to what your doing (the game I mean) then work around that idea and throw some concepts around with other people you work with. I would suggest doing some reasearch on the age group you have mentioned, to get a better idea as to what there style and what they like is, but I imagine you would of already researched that if you`re looking to make a game that is that specific an age group.
Imagination :: A recombination of mental images from past experiences into a new pattern.