Write an outline of your novel. The outline only needs to roughly cover major plot points. You will flesh out these items as you write.
Construct backgrounds for each of your major characters. What are their personalities, family backgrounds, educational and job histories? Who are their friends? What challenges have they faced? How do they know one another?
Choose a setting for the novel. Consider using places you have visited or the city where you live. Choosing a place you know well will add an air of authenticity to the novel.
Begin writing the first chapter. Don't spend a lot of time introducing the characters and explaining their backgrounds in depth. Start with some action or some dilemma from the beginning in order to draw in the readers and make them want to continue to read your novel.
Review the first 10 chapters that you have written. Edit for spelling, punctuation and grammar, but also evaluate how the novel flows. Is the plot progressing? Are your characters developing? If not, it's time to make some revisions.
Complete the first draft and let your novel sit for a week or two. Review it and ask yourself if the dialogue and characters seem realistic. Take the time to completely resolve any major plot problems.
Ask a friend to review the novel when you are happy with it. Ask her if the characters and plot seem believable and interesting. Find out if she thinks that you have adequately described the setting and characters.
Query literary agents when you are satisfied that your novel is the best that it can be. Your agent will contact publishing houses on your behalf in order to sell your book. You can find a list of agents at the Writers Net and Writers Market websites (see Resources for more information).
Work with the publishing house editor when your agent finds a buyer for your novel. Make the final revisions and wait for your novel to hit bookstores. Be prepared to do some marketing on your own to help sell your book in bookstores and on the Internet.