Basically, there are three things to consider when composing a shot. The subject, the context and noise.
The person, object or view that you are attempting to capture.
Anything else around the subject that is relevant to it and enhances the message of the picture.
The idea of good composition is to capture the subject in enough context to produce a powerful image with as little noise in the shot as possible.
Here, both the female and the Roman ruins are the subject in the context of the Tunisian desert. A closer shot could have produced a view where the female was the subject in the context of the Roman Ruins.
This far off point of view causes the female and the pillars to merge visually. The figure sits on a low slab, balancing off the missing pillar and the other columns, through their varying heights, take on the look of a family group.
The distance also adds to the silent tranquility of the scene.
Potential noise intruding into this scene would include tourists wandering in from the side or a Land Rover bumpping across the desert behind.
A female bowling is the subject of this shot, in the context of an old traditional English pub.
The two men at the table to the left drinking and the man standing to the left in the background are all context, rather than secondary subjects.
The men drinking help establish exactly where we are and the man to the rear is watching the wooden skittles and focusing his (and our) attention on the subject.
Additional people lining up to bowl (who were actually there, but cropped out of shot) would have made this shot cluttered.
Other potential noise would be things like extra activities confusing the issue such as a game of darts ensuing somehwere within the scene.
This photograph shows the tail end of a carnival as it reaches the end of its procession route. A marshall and a Police biker are the primary and secondary subjects respectively.
The radiant carnival float itself is merely part of the context here. The first version of this shot was a landscape scene including a burger van to the left. This upset the dynamic of the shot and made it too cluttered.
In this portrait version the road markings and telephone wires (behind the street light) add to the extreme persepctive. The street light itself frames off the left side and points us back into the centre of the scene.
On the other side, the top of the luminous float draws a line of persepctive between the two men and further emphasises the scale difference.