I'm just a beginner myself, and by no means qualified to critique anyone else's art, but hopefully this is still helpful!
I'd recommend seriously increasing the brightness and contrast of your colors. You have a lot of very similar, very dark colors, which are pretty hard to tell apart; in fact, there are a bunch of colors that don't actually appear in your palette (highlighted in red):
Because of this, lot of the detail you've put in is pretty much impossible to see at native resolution, or even blown up— I couldn't even see the red belt until I until I started mucking around with it in my editor! This is a super quick-and-dirty color edit, so it doesn't look particularly
good, but it's a lot easier to make out:
(actually the red belt still isn't really visible. do as I say, not as I do...)