There's no real answer to that. "Success" is in the eye of the beholder. Also, with any type of art - music, writing, painting, etc - what one person thinks is crap, the next person may think is fabulous.
If you're talking about success in terms of becoming a famous published writer - I guess your goal should be how to relate to the most amount of people in order to get them to like your work, thus making you popular.
In my opinion, success comes when you find happiness in what you do.
Good luck to you!