For lighting you might consider seeing if you can find an HDRI (HDR) for lighting of a store or see if they will support you getting the equipment to make one for yourself. 

I know you don't need to do live video and 3d objects but if you ever do try the free voodoo or commercial syntheyes. 

Here is a discussion on HDRI in carrara http://forum.daz3d.com/viewtopic.php?t=66675
and this is one using HDRI as a plugin for DS but this is to a specific post to see the lighting done with an with and without HDR  http://forum.daz3d.com/viewtopic.php?p=1207038#1207038

That being said I haven't learned yet to do the HDR stuff myself yet.

Here are some store Interiors - Its a commercial link http://www.doschdesign.com/products/hdri/Shop_Interiors.html