We must therefore use some illusion to render a pastoral delightful; and this consists in exposing the best side only of a shepherd’s life, and in concealing its miseries. Nor is it enough to introduce shepherds discoursing together in a natural way; but a regard must be had to the subject; that it contain some particular beauty in itself, and that it be different in every eclogue. Besides, in each of them a designed scene or prospect is to be presented to our view, which should likewise have its variety. This variety is obtained, in a great degree, by frequent comparisons, drawn from the most agreeable objects of the country; by interrogations to things inanimate; by beautiful digressions, but those short; sometimes by insisting a little on circumstances; and, lastly, by elegant turns on the words, which render the numbers extremely sweet and pleasing. As for the numbers themselves, though they are properly of the heroic measure, they should be the smoothest, the most easy and flowing imaginable.
Alexander Pope: Discourse on Pastoral Poetry