The background should be white or off-white. A white wall in your home will work.
Take a passport photo with the subject facing forward. His eyes should be open and there should be no major shadows or glare on his face.
Make the photo 2 inches by 2 inches. The subject's face should be centered in the picture, and his eyes cannot be more than 1 3/8 inches from the bottom of the photo.
Photograph the subject with a natural facial expression. Funny faces will not be accepted.
If you would rather have a passport photo taken for you, you can have this done at most U.S. post offices and some drugstores. The post office is the safest of all options.
