I imagine it's a very small percentage of SketchUp users who take advantage of Styles, which control how your model is displayed. A SketchUp style can control the edge color, face colors, background colors, watermarks, etc. There are a few style included in your SketchUp download, and of course you can create your own.
SketchUp Artists is a website that provides a ton of "beyond SketchUp" information, such as tutorials on rendering applications and techniques for presentation. They also have a Styles page where you can download some beautiful styles created by talented SketchUp pros around the world.
As an example, I downloaded the first style on the page ("Style 5" by Jean-Luc Clauss):
Clicking on the image on the Styles page enables you to save the style as a ZIP file. Extract the file it contains into one of the folders wtihin the Styles folder of your SketchUp installation.
In my case, I created a "JLC" folder (for Jean-Luc Clauss) inside my Styles folder.
And the "Style05.style" file was extracted into the JLC folder.
When opening SketchUp, I located the JLC folder within the main Styles collection of the Styles window:
Opening the JLC folder shows the style I placed inside.
Here's a model I downloaded, which is shown in SketchUp's default style.
Clicking the "Style5" thumbnail transforms the model into a rather stunning non-photorealistic presentation, complete with a neat Japanese-style mountain and tree in the background.
Anyone can design anything in 3D! http://www.3dvinci.net/