When shooting a dark colored object against a dark background, one challenge is that the edges of the object tend to get lost in the background. Here are two ways to deal with this:
1. Light the background to add separation. This it the technique I used in my last post.
2. Use rim lighting to clearly define the edges of the object, as shown in the photo above.
The key to this kind of rim lighting is hard, directional light, so that the light goes exactly where you want it, and nowhere else. Good lighting is often about what not to light, as much as it is about what to light.