you know what i have done, that is both interesting and informative, is i have kept a library of photos, from the same spot, from different times; like one from 2002, one from 2003, etc, etc.
It is like a journal, per se. It lets me look at what mistakes i made in the past, and how far i have come along. Ofcourse public opinion is great as well.
The most important aspect of photography (well there are several) is the understanding of the technical side of photography. Why does a wide open aperture look different than a small aperture. Understanding exposure and ISO (the sensors' sensitivity to light, film; back in the day)
I would read up on some good books. I know it is daunting to find a great book, as everyone seems to want to jump on this digital bandwagon.
The book i bought is called "photography" by John Freeman. It is an amazing book. And i tell people, don't worry if the book isn't 2009. Techniques don't go obsolete.
Also, post processing techniques come into play as well. The nature of shooting RAW is to be able to PP the files w/o a loss of quality to the file. Also, RAW is NOT sharp out of the camera.
One last thing that i do. Since i learned how to shoot on film, you had to be careful and aware of the settings of the camera and the lighting around you. Ofcourse with film , it would be days before you saw your results, and if you were far away from your house and you effed up, you are out of luck. You took pictures with care. That is how i do it, even with digital. You can only salvage an image to a degree