A good book has the following:
Three dimensional, believable characters
A resolution to the conflict
You need to have some sort of conflict in the book that is presented right from the start. The conflict must be resolved by the ending of the book. This does not mean that your book has to have a happy ending, but you cannot leave anything hanging out there that remains unsolved. You also want to craft your book so that it reaches a climax, which builds up throughout the book.
Another thing that you need to determine is which point of view you want to use to write the book. You can choose first person narrative, which is an easier style to write but is limited to the thoughts and actions of the main character, or narrator of the story. You can write first person observant which tells the story from the point of view of another character who is observing the action. You can choose third person and still write from the point of view of the main protagonist. When you are writing from the third person, you can also delve into the point of view from other characters in the book. Of all styles of writing, third person omniscient, which sees into the heads of all the characters, is the most difficult to write. Take a look at books that you like to read and see which writing style will best fit your book. The point of view that you write from can make or break your book. For example, the Sherlock Holmes books by Sir Arthur Conan Doyle were a flop at first, until he changed the point of view coming from Dr. Watson, which was first person observant.
In addition to point of view, you also need to decide if you are writing in the past or present tense. Most books are written in the past tense, although you may want to take a look at “Presumed Innocent” by Scott Turow to see an example of first person narrative in the present tense. Writing in the present tense is more difficult, but lends more action to the book.
Do your research by studying other books and your own writing style to see which point of view and tense you wish to use in your book. First person narrative, which is also called prose writing, is the easiest, but has limitations. Third person omniscient is the most difficult, but opens up the thoughts and feelings of other characters in the book. This type of research should be done before you start your book, but can be changed if you find that it is not working for you and how you want to tell a story.