While you may like free-form writing, which is writing without doing any sort of outline, you should still have an idea of the ending of the book in mind. When you are writing fiction, characters tend to come to life as you write and your ending may change as you rewrite, so it is important to be flexible. If you prefer free-form writing, then just start writing and the ideas will start to flow. You can rework characters and plots as you move on in your book. Everyone has a different style when it comes to writing books. Over-thinking the book and too much planning can bog you down and keep you from writing. Too little thought can keep your book from reaching a conclusion. It takes a lot of creativity as well as some structure in order to write a successful book that people will want to read. You should read books in the genre that you are interested in so that you get the feel for this type of writing and in addition, reading is a good way to improve your writing skills.