How do I get a shiny silver color?
Wilton has a product called luster dust in silver. Dust this on with a small brush, or add voka or lemon juice to use it as a paint. Hope this helps!
What are you trying to accomplish? Are you trying to color all of your fondant, or are you wanting to color decorations?
If you want to color a whole tier/cake, I would recommend airbrushing. You can buy metallic airbrush color. If you don't have an airbrush, you can buy canned metallic spray color.
If you want to paint metallic color onto a decoration, you can just buy metallic luster dust and mix it with a little bit of vodka.
If you are looking for a very shiny, almost metal look and lustre dust is too "soft" shall we say, you can use disco dust, comes in the same little pots like lustre dust but so much more shiny.
And yes, airbrushing is also a good way to go.
If you are doing small sections, I would recommend dry dusting (I use a make-up brush) grey fondant with lustre (or pearl) dust. You will be happier with the results than if you painted.