Brevity has its limitations. Sometimes more words save more time.
Horizontal Expansion
You can move from effect to cause, or from cause to effect.
You go to a new but related idea: and, on the other hand, next, therefore, thus, which leads to, consequently, …
Vertical Expansion
You may provide examples, descriptions, illustrations for reader to infer the idea, what your subject is not, comparisons and contrasts.
It’s a method of analysis, detail and illustration: for example, in particular, on closer examination, which is not, the causes of which are…
Generalities require particulars, abstractions require concretes, opinions require evidence.
Example Paragraph
If automobile pollution continues unabated, we can expect an increase in a good many social and physical diseases in our large metropolitan areas.
(VE) Automobile pollution - in current doses - definitely contributes to the high incidence of cancer, bronchial ailments and to the high incidence of social dissatisfactions and to the general deterioration of our ‘quality of life’ with the blighting of our parks, lawns, etc.
(HE) And if our large metropolitan areas become increasingly diseased, the entire fabric of American culture and economy will be threatened.
(HE) Surely it behooves the American public to protect its ‘health’ on all fronts by insisting on regulations and ordinances curtailing the use of the automobile in modern society.
(VE) Such regulations and ordinances will have to restrict the licensing of drivers, regulate the kinds of fuel to be used, prescribe the actual construction of automobile engines, and the like.
Exercises
Transform generalities, e.g. few novels make good movies, or communication failure is the world’s tragedy, into meaningful statements by fleshing them out.