Sometimes drawing something well requires seeing a good example or a tutorial and "clicking" it with your own style and abilities. Recently, before I start drawing something, I look for some references even for things I know how to do. You can always learn something new.
The problem with following the nature is...well...the communication between your eyes and your hands .
Thanks for those links! I already know some of those artists, but not every of them. Their drawings may be useful one day .
Also, believe me or not, while drawing my most recent work (about birds), I've been thinking about the way you draw wings. Not directly, but it was something like "oh, I remember I wanted to make more fuzz on the wings". The influence may not be so visible, but I tried .