It is a matter of our personal taste how far we push the process of abstraction. For instance I like to remove colour or reduce it's saturation. On the other hand modifying colour, by switching colours or increasing saturation rarely produces a pleasing effect to my eye,
Composition is the strongest means of producing abstraction. We take a scene and isolate elements that are of interest to us paying particular attention to how those elements relate to each other. This isolation removes context; when there is no context it is often difficult to judge at what we are looking.
Here are a couple of example shots. The first is the face of a building with no reference to the ground on which it stands. The profile of the building against the sky is interesting as is the texture of the building. In this case the picture is monochrome but in reality the only colour was that of the sky, the building is grey.
I find this process enormously entertaining; the wealth of such subject all around is is staggering.