If the reader, literally or figuratively, can laugh or cry with the people in a story; if he can put himself in their places -- however different their type-script situations; if he can say, "That's what I would have said or done under the circumstances"; if he can leap from page to page in a fever of anxiety to see what happens, good ending or bad; and if he lays the magazine or book aside with the feeling of having lived, for a little while, a life like his own, or a life such as his might have been or might yet be, or a totally unknown life which still holds for him the sense of validity, then you've written a good story.
The touchstone is, do you believe it, as you write?
You have to believe it, you know, or no one else will. The souped-up, the dressed-up, the overwritten, the superior attitude of the godlike writer moving pretty little puppets around a pretty little stage, against a fine backgroud, is just no good.
The great books, if you will take the time to read them again, have valid emotions; they are peopled with realities; they move you, sometimes against your will, and they will endure. Any book or story worth the paper it's printed on must have genuine emotion, communicated by the writer to the character and by the character to the reader. It must have, as well as technique, a spiritual content.
Write from knowledge; learn your techniques, but remember that the great quality is not learned even by experience in writing, for it is the quality of understanding and compassion, and of objectivity as well as subjectivity, so that you can see your characters up and down and around and inside and out, and know what makes them tick ... no matter who they are or what they do. Learn to know them -- by heart.