Here are some very useful YouTube videos that discuss advanced lighting principles.
1) Cinematic Lighting Techniques: https://www.youtube.com/watch?reload=9&v=eZ5hpcn6tIM
2) Daylight vs Tungsten: https://www.youtube.com/watch?v=udCyyUaEs6E
3) White Balance & Kelvin Explained: https://www.youtube.com/watch?v=48c02L_nHZc
Lighting can make all the difference in the look of your video. It can make a picture look dull and flat or rich and colorful. Outdoor lighting is one of the trickiest because there are a lot of factors beyond your control. The lighting can change on the fly if cloud rolls in, and the time of day has a direct impact on how your picture will look. Shooting in direct sunlight is harsh and can cause dark shadows, blown out highlights and cause your subject to squint. While shooting during the golden hours of sunrise or sunset can provide really warm pleasing look and a nice contrast to your image. Long shadows help pick out extra details, adding texture and depth to the image.
You can't always use a studio with perfect lighting conditions. If you are forced to shoot outside during the day, try filming in the shade as it will create softer shadows. A cloudy day can also act as a natural softbox and decrease harsh shadows.
Here we have a pleasing halo of light around the subject and nice even lighting across the face. This shot was achieved by placing the sun behind the back of the subject.
Avoid: harsh shadows (sun located on either side of the face)
The placement of the sun really matters! If you place the sun to the either side (left or right of the subject) you could create unpleasant looking dark shadows on one side of the face. In this case the side hitting the light is also overexposed and washed out. Any fine details are lost in the highlights.
Avoid: sun placement in front of subject (behind camera)
If you place the sun behind the camera, it will make the sky look great, but it will cause your subject to be looking directly into the sun. This will cause the subject to squint. If the sun is high up in the sky at noon then it will create dark shadows under the eyes. In this case the subject is forced to squint and his glasses and his neck create dark shadows too.
Do: Sun placed behind subject (in front of camera)
The best way is to place the sun behind the subject at midday, sunset, or sunrise. This is known as backlighting. It creates a rim of light around the subject and is very pleasing to the eye. It also helps to separate the subject from the background. This shot was taken with the sun behind.
Lens flare & silhouette
When the sun is in front of you and behind your subject, just make sure that the light isn't directly shining into the lens and creating lens flare. This can cause your subject to be underexposed. If the sun is directly behind your subject you can create a silhouette.
Generally, a properly lit indoor space will give you a good result. When working with overhead lighting, you may need to adjust your subject forward or backwards to avoid top lit shadows.
Here we have the subject standing in front of an overhead light. This isn't good because it casts him in darkness.
If the subject steps directly underneath the overhead light the shadows will be just as bad. You can see the subject a little better, but the light still casts dark shadows down across the face.
The best way to use indoor light is to have the subject stand with the overhead light further in front of them. The light casts over his face more uniformly now.
If you can, try aiming some light directly at his face from the front side of the face. One light should be brighter (the key light) and the other about half of the intensity on the opposite side (the fill light). The key is on the right. The fill is on the left.
Lighting in a studio is typically controlled using a 3-point lighting system. First you have the key light, which is the brightest light in your scene and located on one side of the camera. With just the key light shining you would have jarring shadows on one side of the face so it's important to use a fill light.
The fill light is always placed on the opposite side of your key light. The fill lights job is to fill in the shadows for a softer, more pleasing look. The light intensity of the fill light is usually about half of the key light. A softbox or diffusion screen is a common cover piece to a fill light.
Finally the backlight is the third light in a 3-point lighting system. The backlight is placed behind your subject to either side. It gives extra separation between your subject and the background and creates that nice looking halo or rim of light around the subjects hair and highlights contours for a more professional look.