Lighting is one of the most important factors when creating a video. Without good light, a video will often come out looking dull and grainy even if you're using a high-quality professional camcorder.
Things to consider
Multiple light sources
This is the main light. It is usually the strongest and has the most influence on the look of the scene. It is placed to one side of the camera/subject so that this side is well lit and the other side has some shadow.
This is the secondary light and is placed on the opposite side of the key light. It is used to fill the shadows created by the key. The fill will usually be softer and less bright than the key. To achieve this, you could move the light further away or use some spun. You might also want to set the fill light to more of a flood than the key.
The back light is placed behind the subject and lights it from the rear. Rather than providing direct lighting (like the key and fill), its purpose is to provide definition and subtle highlights around the subject's outlines. This helps separate the subject from the background and provide a three-dimensional look.