One thing you could do would be add a gel map to one of your lights to
give the lighting a ripple effect.  Check some of the previous threads
on lighting to get some ideas how to do this.

As to how they do those great images, practice, practice, practise.
Some of these people have been doing this stuff for years.
As of yet Poser doesn't have a "Make Art" button, you still have
to work at it.