Context arises when you think about the theme of your photo. What are you trying to portray? What is the main subject? Context is anything that relates to that, which can logically be included in the picture. For example, using tree branches, an archway, a doorway, or a window to frame a picture each conveys a different impression about the setting, which may related to different themes, ideas, and main subjects.

Including other objects besides your main subject can also add context (of course this is easier to do in an arranged photo such as in a studio). For example, if the subject is a musician, context could include a musical instrument; if a scientist, a lab coat and laboratory equipment, or a blackboard with equations could provide context; if your subject is a woman about to go out on the town, her clothing and surroundings can be chosen to reflect this theme. Be aware of all the details that will appear in the photo and make sure they all fit together, and that each is correctly emphasized.