Use 3 Point Lighting. This means you have three types of light: Key, Fill/s, Back. The Key light is the main source of illumination (sun, lamp, and so on). This should be the brightest light in your scene. Next are the Fill light/s. These lights soften shadows in the scene. Fill lights are usually much dimmer than the Key light. Also, they should be lower (Y-axis) than the Key light, as well as on the opposite side of the Key light usually. Lastly, the Back light is used to create an edge on the object/s in your scene. This is best when you have objects of the same color in your scene (blue ball against as blue background, for example). Position this light in back of the object/s in your scene and make it as intense as needed. To fake radiosity: point dim, colored lights in the direction that the light would be reflecting or bouncing. So, for example: there is a room with a window. The sun is shining in the window onto the floor. The floor is brown. So, you'd add dim, brown light/s and aim them at the wall and ceiling to fake radiosity.