Steven J. Clark
Start writing! I meet so many people who tell me they want to write a book but have never begun writing. No book ever got written until someone's butt hit a chair and their fingers (or pencil) started to move. If you never make that butt/chair interface, all you have is an idea. And ideas are worthless until you begin to make them a reality. The next most important thing is to finish it. A half-written book benefits no one except the author in who's head the idea still resides. If you want to be an author, start writing. It's the only way I know how to do it.
The other problem people tell me about is that they "don't know how to write" or don't know how to write well enough. The solution is the same. Start Writing! Good writing is best and easiest learned by writing. Take a creative writing class at a local college. Join a writers' support group. Let friends and acquaintances critique your work until it feels right to them. It doesn't matter if your work sucks at first, All of us put out crap until we practiced and learned how to produce commercially viable work. But none of that can happen until you get your butt into that chair and start writing.