Determine a premise for your book. This should be a brief summary, in no more than two lines.
Decide on a hook for your story. This makes up the beginning of the book, and may be in the form of something your main character wants to achieve or a problem he has. You need to develop an idea that will leave the reader wanting to find out more.
Create a point of conflict in your plot. This could be a literal conflict, between characters, or more of an internal or metaphorical conflict within the thoughts of your protagonist. The conflict will be present throughout the middle of your book.
Invent some sub-plots. These are especially important if you are writing a novel-length book, rather than a novella, because it is unlikely that your main point of conflict will provide enough material to fill a 300-page, or longer, novel. Sub-plots also make your character more believable and less one-dimensional because, as in real life, no one has just one experience occurring.
Develop a resolution for your novel. This is where the conflict is resolved and all the threads of the plot are tied together. Your main character should learn something and perhaps grow as a person.