Writing your "Great American" novel is the easiest part of producing a book. The joy of developing characters and becoming involved in their lives presents you with friends who never let you down. Your setting can be anywhere in this world or beyond and the premise of the story gives you an opportunity to spout off on topics near and dear to your heart. You can get away with more in your writing than you can if placed on Facebook or other social media.
After you have perfected your work, the real job begins. Finding someone who believes in you and your work is the most difficult part of getting published. My best suggestion is to discover a conference that speaks to your genre and go. Jump in with both feet. Conferences are the most effective way to find out what you don't know and make friends who are as passionate about their work as you. It will pump you up. Make sure that the conference employs editors, literary agents and publishers and that you will have the opportunity to speak to them on several occasions. Before you go, create a one sentence pitch that will dazzle. If you don't know what that is, go on the Internet and look it up. You can find anything on the Internet.
Do not expect a publisher to accept your work unedited. Many fiends are eager to be the first to read your work. Ask several, giving each something different to focus on. If someone can be trusted to line edit, all the better. Have one look for content, another for specifics: people are wearing the same outfits on the same day or their appearance and if it changes with time, or checking for unnecessary adjectives.
Of course there is more. This is just to whet your appetite.