Write down on a piece of paper a list of events or scenes, in sequence, which make up the plot of your novel. Also write down a list of the novel's characters. Make sure the characters are well defined and your readers can relate to them. A good test of a plot is that, no matter how complex, it can be summarized in a single sentence. As an example, "Gone With the Wind," by Margaret Mitchell, can be described as, "A southern debutante finds and loses love during the Civil War."
Expand the list of items in your plot into a chapter-by-chapter outline of your novel. At this point, look for opportunities to refine your plot and any subplots in your novel. In some cases your plot may not be linear in time, and you will have "flashbacks" which go back in time, or even "flash-forwards" which jump ahead in time. Be careful with these devices as they may confuse the reader.
Check your plot as it flows through your chapter outline to make sure that it will hold the reader's attention. Eliminate any parts of the plot that don't advance the story. Don't let your novel digress. You may have some subplots in your novel. Still, the entire novel must work to achieve its climax which should come at, or very near, the end of the novel.
Start writing your novel. As you do, you will have the opportunity to see where you can make improvements in your plot. Your plot is not set in stone. After you finish the first draft of your book, there is more work to be done. Edit the first draft of your book very carefully. Make any necessary improvements to your plot, writing and elements of style, including punctuation and capitalization. Look for the common pitfalls of writing something that is not part of your story, or of being too wordy. Do not hesitate to eliminate anything that diverges from your plot. Make sure that the pace of your novel and the unfolding of its plot keep the reader interested. Your goal must be to turn out a novel written to professional standards and, most importantly, with a great plot.