So I'd think consumer behavior data / demographic data / etc. is a useful guide, but I'm not sure it's sufficient in and of itself.
All of that said, Alan Kay said something interesting in a set of lectures he did a year or so ago. He brought up the idea of basing new product ideas on "Human Univerals", or universal aspects of human nature that really don't vary. A writer named Donald Brown wrote a book literally titled Human Univerals which catalogs a number of these (a lot of them are pretty obvious though: food, shelter, sex, etc.). Kay suggested reading this book, pick one of the human univerals, and figure out a way to use technology to address that.
The book is expensive, here's a list:
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