Consider the background
If you photograph someone against a bright background, you may well end up with a silhouette. That's because the brightness behind can cause the camera to underexpose the subject, making it appear dark. To counteract this, you could pop up your Nikon DSLR's built-in flash, or turn on the flash function in your COOLPIX or Nikon 1 digital camera. But while you would add light to the face, you'd still have the problem of that bright background.
Every Nikon DSLR and COOLPIX has exposure compensation. Overexpose by one or two f/stops or shutter speeds to offset the brightness of the background. If the results are still not what you wanted, try a different background: preferably one that's darker than the subject.
Keep in mind that the picture is about your subject. Don't shoot the entire area around them. Get closer by physically moving in, or by using a telephoto lens or zoom lens. Isolate your subject against that simple background you found. People's heads are vertical, so shoot them that way. Horizontal portraits can look uncomfortable.