This tutorial will teach you how to create quick realistic chrome effects using Photoshop's Layer styles.. Please note that there is no single way of doing things, and these steps are simply my own way of working, you can experiment with your own style to find easier/better methods. This was created in Photoshop 6.

Start with a new Document in Photoshop, make it any size you want, I started with 400x400 px.
Fill the background with any color, preferably a dark color, I used dark grey.

Now we're going to create the ring shape.
Fill the selection with grey # 686868 and keep the selection, then go to "Select > Transform Selection", holding down SHIFT and ALT, decrease the size of the selection inwards, depending on how thick you want your ring to be.

Press ENTER, then DELETE to get the ring shape.

Now, we're ready to apply the layer styles.

Finally apply this stroke, and add a default Drop Shadow.

You should get something like this.

Now, if you want more/less shiny chrome, you can play with the Bevel and Satin styles, you can produce countless effects. Remember to save the styles to the styles palette for quick use later.

NOTE: This effect works best with circular shapes, like this ring.