It's been ages since I posted on here. Anyway...
So I dunno about you but for me a picture speaks way more than the 1000 words everyone quotes so:
Personally your colour pallet was a bit too much for such a small piece. I culled it down.
Next off try adding more contrast to the smaller amount of colours. I don't just mean by going darker or lighter but add some blues to the shadows and yellow to the light sources. (I myself generally use green for light and purple for shadow but that's a bit hard to do on a green lizard thing)
Next when shading try and think of the creature made up of shapes and image how said shapes would be shaded. I always add a line of shadow above an eye and a line of light below an eye to show indention. It's a bit of an exaggeration but exaggeration can be good in pixel art.
I'm personally not a big fan of black outlines on small pieces as it takes away room you could use for details but it's all about stylistic choice in the end.
Also try not to use full saturated colours. (where sat = 255) unless for a particular reason as it makes the whole thing blend in my oppinion and is intense for human eyes.
Also when he lays down I'd cut off more than his legs as if he truly were hidden against the ground. Even just another pixel or so.
Yeah anyway hope that helps a bit. (Bit hard to pixel as my current laptops screen resolution is screwed megarly, hence the little posting)
