My approach to composition depends on the subject matter; in the landscape my first consideration is the light, I photograph where, in my opinion, the light is at it's best or most interesting and when I have decided on that I investigate point of view. I never look through the camera or use a viewing filter, I select the area that I find interesting first, simply by forming a frame in my mind's eye and then decide on where to place the camera. I do this by bending my knees or climbling convenient higher viewpoints to put my eyes where I want the camera to be until I find the preferred viewpoint and only then do I set up the tripod and camera in the position that I have just placed my head. Because I am most interested in photographing the light this process happens very quickly.
When photographing on the street my interest is events and expression so composition is very much a secondary consideration. Only when I'm interested in juxtaposition do I spend time looking at composition.