There is a youtube channel hosted by Tyler Edlin, a freelance artist who holds BST Challenges where every month you can submit an illustration based off of a theme that he selects (Damsel in distress, creature design etc etc). Then he, along with another professional artist get together and critque everyone's work. So far I've just sat back and watched others, but this month I pulled up my pants and entered the challenge myself. The theme in this challenge was Design a Rebel Base.
My entry is in, the critique video is up. They talk about my piece at ---> 46:55 minutes in. <---
I'm glad I did this, I get a lot of useful feedback from this and I'm ashamed that I haven't done it sooner.