If you want to reduce hot spots and spread light over a greater area, be it sunlight or an artificial source, use diffusion paper, also known as a china ball. It softens the light to remove shinny spots on an actor's skin or elements of a set. The farther the diffusion is from the light source, the softer and more spread out the light will be.
If you're experiencing shadows on set, or need to increase the intensity of light in a specific area without affecting the rest of a set, use a white foam board or silver/gold reflectors. They'll redirect light to specific areas to "warm" or intensify the light, as is the case with gold or silver reflector panels.
For indoor lighting, which requires a softer effect, use "3200K" bulbs, often labeled as tungsten quartz halogen. This bulb produces light similar to that of a household incandescent bulb. To remove shadows outdoors and/or mimic the color tone of daylight, use "5000K" bulbs, often referred to as daylight or full-spectrum bulbs.
Clip colored film sheets over an artificial light source to change its color temperature. Place a blue gel over 3200K bulbs to increase light intensity to 5000K, to mimic daylight, or an orange gel over 5000K bulbs to decrease a light source's intensity to 3200K, for indoor lighting. Always ensure lighting fixtures are in good repair before attaching gels.