Bright, direct light will create hard shadows and reflections. Soft, diffused light will soften those edges and help bring out colors and patterns. Dappled light can be a benefit or a curse, depending on the subject. Watch how the light affects your subject, especially outdoors. Light is ever changing, and the alternating shadows and variations of tone will have an effect on your composition.
Light has direction.
Determine whether front lighting, side lighting, or back lighting is most appropriate for your subject. Your eye perceives a subject based on its spatial relationship with its surroundings. From a distant vantage point, a mountain may look small and relatively near other objects in the scene. But when you drive down the valley and closer to the mountain, suddenly it becomes enormous, dwarfing everything else in its vicinity. The other mountains that seemed so near are now completely out of view.