In his 1949 book, Thurber Country, celebrated author, cartoonist and satirist James Thurber offers some amusing rules for comedy writers, "established [...] after receiving dozens of humorous essays and stories from strangers over a period of twenty years."
Those rules are as follows.
(Source: Thurber Country; Image: James Thurber, via Wikipedia.)
1. The reader should be able to find out what the story is about.
2. Some inkling of the general idea should be apparent in the first five hundred words.
3. If the writer has decided to change the name of his protagonist from Ketcham to McTavish, Ketcham should not keep bobbing up in the last five pages. A good way to eliminate this confusion is to read the piece over before sending it out, and remove Ketcham completely. He is a nuisance.
4. The word "I'll" should not be divided so that the "I" is on one line and the " 'll" on the next. The reader's attention, after the breaking up of "I'll," can never be successfully recaptured.
5. It also never recovers from such names as Ann S. Thetic, Maud Lynn, Sally Forth, Bertha Twins, and the like.
6. Avoid comic stories about plumbers who are mistaken for surgeons, sheriffs who are terrified by gunfire, psychiatrists who are driven crazy by women patients, doctors who faint at the sight of blood, adolescent girls who know more about sex than their fathers do, and midgets who turn out to be the parents of a two-hundred-pound wrestler.
Also, I have a special wariness of people who write opening sentences with nothing in mind, and then try to create a story around them. These sentences, usually easy to detect, go like this: "Mrs. Ponsonby had never put the dog in the oven before," "'I have a wine tree, if you would care to see it,' said Mr. Dillingworth," and "Jackson decided suddenly, for no reason, really, to buy his wife a tricycle." I have never traced the fortunes of such characters in the stories I receive beyond the opening sentence, but, like you, I have a fair notion of what happens, or doesn't happen, in "The Barking Oven," "The Burgundy Tree," and "A Tricycle for Mama."