There are several parts to your graphic library. We have already covered using classes for your line weights, colors and line styles. But there are other graphic things you can store in your library. Hatches, gradients and images each have their own folders fro quick access from the Attributes Palette.
The trick with these libraries is to make your own Vectorworks files with the hatches, gradients and images, then delete the standard Vectorworks files from the Vectorworks application folder.