Front lighting illuminates only the parts of the subject that are facing the camera, and is usually considered normal lighting. Because it imparts few shadows, it tends to create a fairly flat effect. Side lighting comes at the subject at a right angle to the camera. This lighting tends to bring out the full effects of texture and form. Morning and evening sunlight usually provide this kind of light.
Back lighting is certainly the trickiest to use.
The camera is unable to capture the image exactly the way your eye sees it, because it cannot register the range of contrasts the same way your eye and mind can when working together. But it also has great potential for high impact, as with dramatic silhouettes. The quality of the light will also have an effect on your subject. Bright, direct light will create hard shadows and reflections. Soft, diffused light will soften those edges and help bring out colors and patterns.