After submitting my game to Steam Greenlight I got a few negative remarks about my art, so I decided to take a screenshot and post it to /r/pixelart to get some educated criticism about what might be going wrong. Firstly I got a lot of positive attention which made me feel nice but what I found amazing and more useful was the criticism that people took the time to write out. Polite, accurate and great advice. I noticed a pattern with many of the comments and have started working on improving the areas that came up multiple times.
In fact, the top comment was so insightful and helpful I made a lot of modifications to my art based on it alone. I also bought reddit gold for the first time for the person that wrote it.