Some bits of advice:
Mirroring Cenaris: How do you get to Carnegie Hall? Practice, practice, practice. The niftiest techniques and wonderful skills can't develop unless they're used often.
Concerning perfectionism: There is a point when continuing to work on a piece of art will just make things worse. One thing an artist must learn is knowing when to stop working on a piece of art and go on to the next thing, be it another bit of art, the next stage in the art they're working on already, or to start over from scratch if the art just isn't working.
Also concerning perfectionism: Never throw away or be ashamed of your older work. Granted, it will not compare well with what you can do now, but for the time, it was your best work.