I think a big ingredient in your good renders, bb, is your attention to the realistic lighting setup and your attention to shaders/textures.

I have been really liking renders I've seen made using Fryrender, which is much more expensive than Poser and works only as a plug-in to mostly more expensive packages except for Sketch Up. Reading the tutorials for Fryrender, I noticed how they kept stressing how important it is to set up lighting the way it would be if it's supposed to be a real location, if that's what you are aiming for, and that even the lights should physically look like they do in real life. And they stress that materials/shaders should be worked on as much as possible to look real. This actually requires mixing in real, well prepared, texture images if need be with the other nodes.

Kevin