Learning the traditional devices of meter, line and sound gives the poet mastery that enables freedom, rather than limiting expression. The apprentice must study the inherited machinery before earning the right to depart from it; imitation of established poets is a legitimate and necessary stage of learning the craft.
In poetry the line, not the sentence, is the fundamental unit, and where a line breaks controls the reader's pace, emphasis and breath. The line ending creates a slight pause and a point of stress, so the poet manages meaning and music by deciding what word lands at the edge.
The poet should write toward an imagined, attentive reader whose presence disciplines the work, treating that reader as a collaborator to be respected rather than impressed or ignored. Holding this reader in mind guides choices about clarity, music and what can be left unsaid.