What makes good rhetoric

The use of persuasive language, for me,  isn't so much if its written in any specific way or a correct way. I feel that if using rhetoric is effective, if it can truly persuade you then its good rhetoric. The question I have is, if good rhetoric means having proper structure or making sure it can effectively persuade you. Of course you could make the argument that proper structure leads to effective persuasion but which one should be the focus? Is there even a certain way to write it?