You too can write the next great American novel - if you change your goal to something else. When people expect to write something "great," often they end up writing nothing at all. The expectation puts a pressure on people that causes many to quit after just a handful of pages.
First drafts are not perfect. In fact, even the most popular writers can write first drafts that are downright awful. The story is really created during the editing process. Every great writer goes through numerous rewrites and revisions to turn those drafts into the books we love. If you sit down expecting to write the "great" novel and your first few paragraphs need work, it can be defeating. Writers will often refer to their "inner critic" which is the voice inside their head that criticizes their words as they go. You need to learn to ignore that voice and not worry if your story isn't perfect at first. Polishing comes later!
Write your novel. Write the story that you are bursting to tell. Write about things that you love or you hate. Write about your passions. For new writers, it is important to work on their own story. Attempting to write someone else's idea, or to write in a genre they don't love simply because it is popular, will most likely end in failure. If you love your story, it can sustain you through the difficult sections.
The process to publish a novel can be even more grueling than the initial writing process. It is littered with rejection and criticism, and is not for the thin-skinned writer.
If you want to improve as a writer, begin by reading anything you can get your hands on. Read books in the genre that you want to write in. Choose books by both classic authors and contemporary ones. Learn what you like and what you don't like in novels. A good book can be an excellent lesson in character development, dialogue, and exposition if you take the time to study it.
You also have to practice. Try and write something every day, even if it is just a blog post or journal entry. Purchase a small notebook just for jotting down ideas as they come to you. The wonderful thing about ideas is that the more you use, the more you seem to have! They multiply on their own.
Put your focus on the writing, and not the end product, and you just may end up with a brilliant new novel.