eTeen.com allproperty.com - best ways to develop?

[greenlake]

I would like to develop these 2 good domains and build sites that should become major players in their areas.
I own many domains but not any sites yet.
I wonder what would be the best way and where to get help regarding developing the CONCEPTS and ideas that could make these sites winners?
I am not talking web design yet, and am not sure who would be best to approach for ideas and concepts.

Thanks