Writers form themselves into the pyramid we see in all areas of human talent and human creativity. At the bottom are the bad ones. Above them is a group which is slightly smaller but still large and welcoming; these are the competent writers. They may also be found on the staff of your local newspaper, on the racks at your local bookstore, and at poetry readings on Open Mike Night. These are folks who somehow understand that although a lesbian may be angry, her breasts will remain breasts.
The next level is much smaller. These are the really good writers. Above them -- above almost all of us -- are the Shakespeares, the Faulkners, the Yeatses, Shaws and Eudora Welty. They are geniuses, divine accidents, gifted in a way which is beyond our ability to understand, let alone attain.
There are two theses, both simple. The first is that good writing consists of mastering the fundamentals (vocabulary, grammar, the elements of style) and then filling the third level of your toolbox with the right instruments. The second is that while it is impossible to make a competent writer out of a bad writer, and while it is equally impossible to make a great writer out of a good one, it is possible, with lots of hard work, dedication, and timely help, to make a good writer out of a merely competent one.
— from "On Writing" by Stephen King