Pick up Lajos Egri book, Art Of Dramatic Writing: Its Basis in the Creative Interpretation of Human Motives. I though I was ready to launch a book until I read Egri's book. He explains how to make the difference in a great story, a story that will be remembered for its character, as oppose to a common story, a nice story.
I feel strongly that any writer who had not read this book has short changed himself and the reading public. But I warn you that after you have read it you will have to reshape your story and that can be painful. But isn't that what writing is about: Pain that leads to Ecstasy once your work is complete.
Check this title out at your local public library! If you'd rather purchase it, we've linked the image to amazon.com where titles are usually offered at a good discount, especially if you purchase them used. Another great place to check is AddALL. Type the book ISBN and click "Find It!" This will look at many online booksellers and tell you where you can get it at the best price.