Look your subject well over before you write a line; decide what are its outstanding features, which are its most prominent characteristics, and what it is absolutely necessary to say about it, in order to give a clear presentment. At the same time, note what is irrelevant to the main purport of your writing, and what is comparatively unimportant.
After all, the mind can only take in a certain amount of detail, a certain number of facts; and as it cannot absorb everything, a limit has to be placed somewhere. Common sense tells us that since something must be left out, it is well to omit the colourless, unimportant data that never will be missed!
In every scene there are always definite points that arrest the attention and give character to the whole, and many other points that really do not make very much difference one way or the other. The artist (whether he be making word-pictures or colour-pictures) selects those points that give the most character to the scene, those incidents which convey the most comprehensive idea of the place and the people and their doings, in the fewest words.
If you are writing a story, it is seldom necessary to describe every thing appertaining to, and every one connected with, the heroine, for example—at any rate, not on her first appearance. Her home, her relations, her dress, can often be dealt with in a few sentences; but those sentences must contain just the facts that give the key to the whole situation.
Probably it will not throw any vivid light on the lady if you state that her drawing-room was upholstered in old rose, and she herself devoted to chocolate; because the virtuous no less than the wicked, the most advanced feminist as well as the silliest bundle of vanity, might all have equal leanings toward old rose and be addicted to chocolate. But if you state, either that she was reading a first edition of Dante, or cutting out flannelette undergarments for the sewing meeting, or powdering her chalky nose in public—the reader will have some sort of clue as to your heroine's personality. An instinct for selection will tell you which item will characterise a person most accurately.
In the same way some incidents will directly affect the whole trend of a story, others leave the main issues untouched. Select the incidents that matter, and leave those that merely mark time without taking the reader any further.
Caricature is not Characterization
But while it is desirable to record outstanding features, it is not wise, as a rule, to emphasise mere peculiarities, as this only tends to stamp one's writing as unnatural, exaggerated, or caricature. Far better seize on general topical characteristics, only select those that are prominent, colourful, and vigorous, rather than neutral, insipid traits or happenings.
People reading Kipling's story, "The Cat that walked by itself," invariably exclaim, "That's just like our cat!" Yet in all probability Kipling's cat was not at all like either of their cats. He merely chose the typical characteristics common to all cats, and each person immediately sees his own individual pussy in the picture.
A lack of an instinct for selection is one of the commonest failings in amateurs, and is responsible for the rejection of an endless stream of MSS. For this reason it is desirable that the beginner should pay special heed to the subject, and note to what extent he is making actual selection, or whether he is merely jotting down all and sundry in haphazard unconcern.