1. Render, Not once...Twice!
A lot of time can be spent tweaking and playing around with Poser lights.
Sometimes you get "some" things looking right... and its often a long process waiting for each render, only to be disappointed, scrapping the setting, and starting over again.
In one of my early days in Rendering (not using Poser at the time) I discovered for myself, in lighting one of my Space-ship renders, that combining 2 identical camera positions with different lighting rigs for each render... created almost endless effects, when put through some layer settings in Photoshop.
Personally I use a really old version of Photoshop, Other alternatives like Open Canvas, Gimp, Painter, also have layer effects such as Overlay, Multiply, Darken, Hue, Saturation...
So use whatever you have.
Also, this is only how I use lights, its not the only way.
Experiment, play, use some of these ideas I'm presenting to create your own effects.
What I will show here is just 2 renders and the combination of these 2 can lead to some cool images.