Lighting can make or break an image. Material room shaders are a big help. A link was given to you above to the material room bookmarks thread.

Here is one on lighting. There is a substantial learning curve to do lighting inside Poser, but it's worth the effort to learn.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2734086

Basically what you need are:

1. a good texture to start with

2. a basic understanding of the material room. There are enough examples around that you can use or tweak to your needs

3. a working knowledge of lighting in your version of Poser. It's easier to make light sets in Poser 6 and Poser 7 than it is in earlier versions of Poser.

4.  a graphic program that you are familiar with.

Then of course in addition to the above you need a creative eye for composition and colour. That isn't so easy to teach.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi