I feel exactly the same way. But one thing I do think I have (and you do too, obviously) is taste. I can look at my code and see it as good or bad (most of the time bad). That means I can keep striving to make it good. And my eye for what is good and bad keeps maturing so when I go look at code I wrote two years ago that I was pretty proud of, I see bad code now.
Without the ability to see that your code can and should be better, your work ethic cannot kick in.
http://www.youtube.com/watch?v=-hidvElQ0xE
He talks about how you get into a creative field because there are works of it which you love and you can distinguish early on between good/interesting and bad/banal work.
But then you start making stuff. And for the first few years, it just isn't very good, and you realize that.
He talks about bridging that gap and how it took him eight (!) years before he started making things which he even recognized as being interesting and good.
It's probably the best piece of advice I've ever seen for people still at the frustrating end of a creative career.
I know too many kids who showed an early eye for quality in some field (architecture, CS, etc) but then gave up out of frustration when the stuff they made wasn't up their own standards.
I read a lot of other people's code. I think that's important to developing taste -- at least as important as writing a lot of code if not more so.