The making of a composition, just like the other elements of a picture , is not a mechanical but visual process.
Whether painting indoors or outdoors, landscape, a group of buildings, a portrait or a single flower… As an artist you need to have a clear idea of what the main elements are and of how you will place them on the paper before you begin to paint.
Landscape out of doors would require you to decide on where your view will start and to its end, where to place the horizon and whether to emphasize or alter features in the background.
For a portrait, still life or flower you would need to decide how much to show, the proportion of your subject in relation to the background, you would consider your colour scheme and the balance of lights and darks.
Composition and selection go hand in hand. As an artist you first select which aspects of the suject are important and then composes the picture by placing them in a certain way.
This essentially geometrical arrangement is enhanced by the use of a proportion known as the ‘Golden Section‘ (or Golden Mean), recorded by Greek mathematician Euclid: The area of the painting is divided by a line in such a way that the smaller part is to the larger what the larger is to the whole.
Good composition is one in which there are no jarring elements; all the parts of the picture balance one another in a pleasing way. The viewers eye should not be led to one part of the painting to the exclusion of others, but there should usually be a focal point
Composition is one of the most powerful means the artist has of communicating with the spectator. It is the skeleton or backbone of the picture.
The other elements add to the total expression and to work well each part must interact with the other to create the emotional impact of the picture.