You've got a lot of superfluous colours, suggesting use of NPA (non pixel art) tools, as well as a bit of pillow shading. Reviewing the basics through a tutorial like this one http://pixeljoint.com/forum/forum_posts.asp?TID=11299 could help you really step up your game. Best of luck!
Hey there!
Thanks for the comment and the link! I'll take a look~
If you got any more tips I'd gladly hear them.