All of these are very closely related. They're all helping by basically taking what you want to say and deciding on how you want to say it. The author's purpose is the message and it drives and informs the rest of the choices/decisions the author makes. It is made up of several different things genre, organization, and details. The choice of genre impacts the idea, organization, and details. Idea is what the author wants to write about. Organization is how the structure of the writing is going to be based on how they want to explore and relay/discuss the idea. Details show what type of information the author is using to talk about this certain topic. Choice of details support the purposed and are used in organization.
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Purpose and genre are intimately connected. The message that an author wants to deliver is connected to the method of delivery. For instance, if an author wants to reveal the complexity of love and friendship, he or she will choose a lengthy work over a short one because of the desire for “complexity.” In addition, the complexity of love and friendship would be something better dealt with in fiction rather than nonfiction because nonfiction typically has a need for “answers,” while fiction deals with possible answers and, more often, questions. Genre is determined by looking at the idea that is being presented, along with the organizational structures and the types of details. Thus, purpose, genre, organization, and choice of details are all interconnected: what you want to say and how you say it cannot be separated.
