As you know, we cannot write your essay for you, but we can help you with HOW to do it. You really have given two separate assignments. Are you supposed to write about the author's views, or about what Holden thinks about people around him? They may not be the same thing, and in any case, are not the same approach.
Let's say you choose to write about what Holden thinks about the people around him. If you write about this, first choose a group of people that Holden has around him because he feels very differently about adults than he does about children. For example, he loves his sister Phoebe and his dead brother Allie, but he does not have many positive things to say about his older brother D. B. who has "sold out" and become a screenwriter. D.B., of course, is an adult. Also, Holden's classmates at Pencey are phonies and he dislikes them, but they are not really children. They are adolescents and on the way to being adults. Most of the adults in Holden's life are phonies, and he dislikes them. Even the ones he thought he liked often disappoint him. So, if you are going to write about this topic, I would choose a group of people and then write the essay about how Holden reacts to this group.
If you are going to write about the author's views, that is a whole other topic - his views about what? Are his views connected in some way to the way Holden feels about people around him? If so, then perhaps you could write about how Holden's view that people are phonies relates to the author's views about phonies in life, or how he feels about alienation. You could also compare what Holden thinks about children to the author's views about the innocence of childhood and how this is lost when one enters adolescence.
For more help, read the "themes" section at the link below.