Lighting in computer graphics is a very important element in creating images. It takes a while of experimenting with different types of lights and settings to get good results, but there is one basic setup that can also be used as a starting point.
The basic approach is one used for lighting real world video scenes. It is known as a "3 point" light setup since it involves 3 light sources.
The first light source named the "key" light is the main light for the scene. It is usually placed about 45 degress above and to the side of the camera. This provides overall light so you can see your objects etc...
The second light is known as the "back" or "top" light. Place this light above and slightly behind the center of your scene. In video this is used to show highlights on a persons hair so you can tell where the back of their head is. In this case, it provides a similar function so that you can see the back parts of objects. This is typically set at about 2 times the key lights intensity, though for computer graphics a setting equal to or less than that of the key is usually enough.
The final light is the "fill" light. This is usually placed at a 45 degress angle below and to the side of the camera so that it is on the opposite side of the "key" light. This light should be dim and possible colored and diffused to give some illumination to any part of the scene not covered fromt the other lights. For rendering this means lowering the intensity and or making the light "diminish in intensity".
With this setup there should be an improvement over any rendering using just one light. As a test setup a ground and a stationary object. (The typical chrome ball with cool highlights on a checkered ground works well here) Render once scene with just one light (the key light only). Then add the other 2 or more fill lights and re- render it. There should be a big difference.
Also, don't forget that lights can be colored, can cast shadows and can be "conical spotlights". All this can be used to give greater value to your scene.