Perhaps you will tell me that it is impossible for you to make these observations, as you do not know your way about any real slum, or you are not on visiting terms with and any millionaire. That raises another important question that I hope to deal with later, when we come to the subject of story-writing. Here I can only say, Don't attempt to write upon topics you are unable to study at near range.
After all, there are unlimited subjects that are close to everybody's hand. You may be including a dog in your story. Is he to be a real dog, or that dear, faithful old creature, who has been leading an active life (in fiction) for a century or more, rescuing the heir when he tumbles in a pond; apprising the sleeping family upstairs of the fact that the clothes-horse by the kitchen fire has caught alight; tracking the burglar to his lair; re-uniting fallen-out lovers by sitting up beseechingly on his hind legs, and in a hundred other ways making himself generally useful?
I am fond of dogs, and I never grudge them literary honours; but I sometimes wish we could get a change of descriptive matter where they are concerned. What are you proposing to say about the dog? "He ran joyfully to meet his master, wagging his tail the while"? Something like that? I shouldn't wonder. That is the beginning and the end of so many amateur descriptions of a dog; and, judging by the number of times I have read these words, his poor tail must be nearly wagged off by now.
Instead of being content with this, start making careful observations, and you will soon have something else to write about. Notice how a dog talks—with his ears; he can tell you almost anything, once you learn to read his ears. And when you have noted all the points you can in this direction, and mastered this part of his language, see what you can learn from his walk; you can estimate a dog's temper and feelings, his sorrow, his joy, and the state of his health, by noticing the variations in his walk. Why, any one dog can provide you with a book full of observations.
You may say, however, that as your story is to be a short one, you could never use up a book full of observations if you had them.
You need a Score of Facts in your Head for each one you put on Paper
Very likely; but always remember that you need to have a score of facts in your head for every one you put down on paper. You must be thoroughly saturated with a subject before you can write even a brief description in a telling and convincing manner. Therefore, never be afraid of making too many notes in your observation-book.
Many of these entries you will never refer to again; the very act of writing them down will so impress them on your memory that they become a matter-of-course to you. This in itself is valuable training; it is one of the processes by which a person may become "well-informed"—an essential qualification for a good writer.
While over-elaboration of detail in your writing is seldom desirable, apart from a text-book or a treatise, knowledge of detail is imperative if that writing is to conjure up situations in the reader's mind and make them seem vividly real. In describing scenery, for instance, you do not need to give the name of every bit of vegetation in sight, till your MS. looks like a botanical dictionary; but it is useful to know those names, you may require some of them; and until your work is actually shaping, you cannot tell exactly what you will use and what omit.
Keen Observation will save you from Pitfalls