In regards to:



Doing artwork for games like this can be as exhaustive as doing photorealistic artwork, just because simple geometric forms and colors doesn't mean that the task is simple at all. Stylizing is in my oppinion a very hard job but the results can be overwhelming.

Getting a feeling for colors is maybe not suited for everyone and even though it comes with experience. If you need a shortcut, tools like kuler should be on your linklist:

http://kuler.adobe.com