Be that as may be, she was in their song. Moreover her voice upon their voices crossed Had now persisted in the woods so long That probably it never would be lost. Never again would birds' song be the same. And to do that to birds was why she came. This is not to suggest that poets carefully calculate all their rhymes, any more they pre-plan all their rhythmical effects.
Good poets learn how to use the tools of their trade and then concentrate on their subject matter.
Paradoxically, intuition and instinct operate most freely in a poem's technical aspects. And it's usually only when things are not working out that a poet will turn his or her undivided attention to the nature of a cadence or the characteristics of a rhyme. At the same time, however, any poet will profit from developing tact and sensitivity with regard to rhyme. Though good rhymes often feature an element of surprise, there are no intrinsically banal or unworkable rhymes. What causes, in poor verse, an impression of weak rhyming is not so much the banality of this or that rhyme, but rather, as Pope indicates, the presence of other insipidities, such as bromidic diction and clich d figures of speech.