"Writing a good book, even an incredible book, will not automatically score you a successful career in traditional publishing. Anyone who tells you differently is either misinformed or sugar-coating it."
I can't stress how true this is. J. K. Rowling got lucky. So did Stephenie Meyer. They started trends rather than riding on the coattails, and in both cases, it just happened to be the right manuscript for the right agent to sell to the right publishing house, and the reading public was ready.