Standard three point lighting

The Three Point Lighting Technique is a standard method used in visual media such as video, film, 

still photography and computer-generated imagery. 

Key Light

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.

Fill Light

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 acheive 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.

Back Light

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.