While the task of writing is often a solitary pursuit, it is only half of the process. Like the proverbial tree in the forest, the acknowledgement of one’s writing is the reader. The reader completes the process. Knowing your audience is critical to your success. The first question I ask any new client is, “Who is your audience?” I guarantee you that the answer is not “Everyone.” 
It is impossible to be all things to all people. Musicians, actors, comedians, and dancers all know their intended audience. Their works are composed and performed to please that particular audience. Your book, fiction or nonfiction, should be written with the particular reader in mind. Think of the books and authors you like to read. Why do you like them? What intimate bond have your favorite writers created? Do the same for your intended readers. Imagine tossing a stone into a still pond, your writing should satisfy the tight inner circle, the vibration resulting from their approval will radiate out. Manifest your reader as you write.