Look at the way that this edit contrasts the colors to form shape.  Your highlights are being squished between the dark border large bulk of the high saturation upon your blue body.
This means that your highlights don't really show up to the eye without close inspection because it's being devoured by the colors around it rather than assisting in shape.

You also used solid lines and blocky shapes to form your dino.  <--another factor that defeats your efforts for form.

Again the edit uses highlights from a defined light source to give the dinosaur a rounded shape.  The colors aren't in a solid batch or a line.  They are sort of subtly reaching around the body to give it both a bit of texture and shape.
Likewise, the underbelly applies a reverse of the same process using darker shades reaching up to show the rounded texture from below..

Shouldn't your base lines match the curve you have already established upon the segmentation of your columns?

BTW I agree completely with astraldata's critique of your colors.  The walls are almost entirely unreadable without focusing really hard on it.
As I understand it, detail work on pixel art is best accomplished when you imply texture with your efforts and color choices.  When a viewer sees the work, that information should be relayed at first glance.  <--If they have to look closely and focus on an asset to read it properly, there is probably an issue there somewhere that could be addressed.

My eyes barely read the details of your bricks on this version.  They are too low contrast between shade and highlight for me to see without squinting and staring at it.
Other critiques I could offer:
Some of your shadows especially around the corners looks too boxy to match the surface.
The shadows of your columns seem to be going at an angle where the other shadows and highlighting implies straight on or from forward and above lighting.  (They don't match)

It's more moving from one color to another rather than from one color to a darker version of that color.
I've been learning the ropes on this myself lately.
http://wayofthepixel.net/pixelation/index.php?topic=2836.0  <-- a thread about it
http://www.planetminecraft.com/blog/tutorial-palettes-and-hue-shifting/ <-- maybe more useful if you read the specifics on which direction to go.
More specifically look at Lucas Kich's edit. Notice how he moved from a bluish gray to yellow and used that lighter blue color as a bridge to get there.
Hue shift from darker color to a brighter and different color.
Bridging is the use of the blue color in between as a middle man. 

I think the biggest readability issue is that straight away the fin that runs the length of her tail appears to be counter-shading (the tendency in animals to have a lighter belly than back because of overhead lighting [camouflage]).
You also have the lighter color from your upper body on the back of the tail which is against natural counter-shading AND her hip area clearly indicates that you are using darker colors on the back and lighter colors on the front which is natural. All of this gives her a spirally-twisty appearance.
It is only upon closer inspection that those fins appear as actual fins. And really only then because of the well defined caudal fin.
Could resolve this with a bit more detail to the fins to make them read more as what they are.  Perhaps some light spine-work within or juncture to body shading?  But your lighting is a bit confusing to the eye.