The fourth quality of the creative type is persistence.
Think J K Rowling not taking no for an answer when twelve publishers rejected her work. Think Colonel Saunders. The story goes that on reaching the age of 65, he realised that a pension was not going to be enough to live on. He had a recipe for chicken he thought was a winner, so he tried to sell it to restaurants in return for a share of any extra profits they made. After two unsuccessful years of selling the idea, he came to the 1008th restaurant, who bought into it. Kentucky Fried Chicken, like J K Rowling, has done pretty well in the years following the big break.
There is a fine line between dogged self-belief and self-delusion (my thoughts turn to some X-Factor hopefuls). But you also have to bear in mind that the world just might not be ready for your particular brand of creativity. Van Gogh, Bizet, Shostakovich and many other artists and composers we now count among the greats were not appreciated in their own lifetimes.