In the beginning, it's best to keep it simple. You'll be overwhelmed quickly if you sit down to write the-next-big-hit-sure-to-be-a-major-motion-picture-in-no-time. To borrow Anne Lamot's analogy (Bird by Bird:), allow your writing to evolve in its own time: brick by brick. Create a shelter for yourself and your characters to feel safe in.
Step One: Write
Better to get your project out of your head, no matter how unprepared and raw it seems. You've been thinking about it for a week, a few months, even YEARS. Lay your groundwork. It's like building a house, you have to start with a frame. Don't wait for all your materials to be there before you start, or your "land" may be swept right up from under you. You have to begin with what you have now. Just start writing, there will be time to set aside the any scrap later.
Step Two: Keep Writing
Don't be like the first little piggies, throwing together your weakest material and thinking it will hold. Have patience with yourself now. You have your idea, you've started to build your frame. Choose your words carefully, but at the same time don't paralyze yourself into thinking that the wrong word at this point will cause your whole house to collapse. Right now, you are just making sure you have all of your bricks available. You're preparing your rough draft. Next you are going to come back to reinforce it.
Step Three: Edit
This is when you come back to build the walls of your writing project. You edit. Make sure the overall themes are sturdy enough to hold up the ceiling of your story. Does each sentence, each setting, each character help the walls of your story stand tall, or are they slightly out of place, threatening to cause cracks and confusion? Take a step back and ask yourself what can be done to make it better. Get rid of the clutter. Decorate with your favorite words and phrases. Take your time, make your writing a place you can call home.
Step Four: On the Market
You've built your work from the ground up, and now it's time to allow others the chance to enjoy it. Invite readers into your home. You may want to try and get help with your "showing". Tell agents and publishers all about your work. Make sure they are the right kind of agents. If they usually sell country style farm homes, they probably wouldn't be interested in your upscale modern studio loft. For your story of modern day love and adventure, find an agent who is at home with romance, not living in a space station with sci-fi clients.
In this day and age, many people are going the "for sale by owner" route. Without the expertise of an agent or publisher on your side, you will need to find your readers by yourself. Location, location, location are the three most important words in real estate. How will readers find your book? Will you have it available to anyone with internet access or a Kindle by using Smashwords? Will you use a print on demand service like Createspace to have your little piece of home delivered via FedEx or UPS? Will you travel the back-roads and byways with a trunkful of your books and sell them one by one? With any of these ways, you will need to provide a map to your work-- they need to be guided to the places your book is available.
Of course, there are places that are looking for work to bring in readers. Literary magazines, consumer magazines, and anthologies are constantly looking for works to include in their communities. Find your type of work among them and submit, following their "home owner's association" rules-- the guidelines.
There are going to be times, no matter what you do, that the big bad wolf of rejection will be trying to blow your house down. Even if you sustain some damage, you'll be fine. You are learning the tools to remodel your work and reenergize yourself with each room you build.Some handy tools:
Take a look at the construction of a short story, from idea to publication: Ron Carlson Writes a Story
Must-have for any writer:The Elements of Style
To find agents, publishers, magazine/newspaper/screenwriting markets, and more: 2010 Writer's Market Deluxe
What is a literary agent, anyway?: http://www.agentquery.com/writer_la.aspx
Current Contest and Markets: Right Here! The Excuse Edtior Scoop has over 35 places looking for your writing right now. Get it every month by signing up for the newsletter right here at http://www.excuseeditor.com/.