What a question! Someone has already posted "Marketing and self promotion". If you are in photography for the $$$, then it is important to know the market. Some markets like the "crap" and some markets like the "Art". Knowing which market to submit your work to, is the key to the $$$. A good book to read is "The Photographer's Market", it can be found at almost any bookstore. If you are in photography for the pleasure of it, then simply shoot anything you want, and if you like it, that's all that really matters! There is one word the describes a "Good Photographer"; CONSISTINTCY.(Probably mis-spelled).