Attached Link: http://www.awakemm.com/poserarcana/

You might like to have a look at the lighting tutorials at Poser Arcana - see the link. You have to think in terms of a virtual photographic studio when lighting Poser scenes, and remember that the view window doesn't give you much of a clue regarding lighting subtleties. You'll need to do lots of test renders to check your progress. I also find that I nearly always have to increase the shadow map size for my main light at least - usually to 1024, but sometimes as high as 4096 if the shadows are a prominent part of the composition or are falling at an oblique angle. Other than that, my best advice is to keep practicing ;-)