Mike Johnston of The Online Photographer just posted a characteristically insightful piece on becoming a "successful" photographer. (I put that in quotes because he’s talking about more than one kind of success.)
The real gold is in the last section, How to know. The significant idea is this: "If you use the 1-2-3 method of editing, you might consider starting a new category: significant failures."
Read the rest, it’s short and worth it!