Opponents of Computer Graphics as an art form are often tempted to fall for the myth that making images on a computer is as easy as a few ‘point and click’ operations, and therefore remove all technical and artistic value to CG creations.
What they seem to forget is that CG graphics are governed by the same rules of composition, lighting and color as photography, painting or drawing. Computers may make some tasks easier, but they do not replace the ‘eye’ and experience of the artist.
If you want to improve the way your CG images look, especially if you are just beginning to play with tools such as Vue or Bryce, do not understimate the value of going over material written for natural media. The tools may be different with a computer, but the basic techniques are the same.
A very simple way to improve dramatically a CG image is by taking control of the lighting. Start by reviewing basic concepts on this great tutorial about Lighting Techniques by Amaan Akram.
Once you are done with this introduction, you can start taking control of your lighting by following this tutorial about the Three Points lighting technique, an excerpt from one of the main bibles of CG Lighting available in print : [Digital] Lighting and Techniques by Jeremy Birn.
You can finish by reviewing "3d Lighting Setups: 3 Point Lighting" by Jenn Downs, as a practical example of how to apply this technique to a particular software package, 3D Studio Max, although if you can read past the specific details of this application, it should not be very difficult to translate it to your favorite 3D package.
Once you start applying these techniques to your own images, you will be amazed how much impact the right lighting can have. And if you get carried away like I did, you will start noticing how light is composed in anything you look at, from movies and paintings to everyday scenes.