First revamp.

[Tiemen.M]

I don't like the right leg but..

 

[OmegaDragon]

Its good for your first, but can use some work. Your main problem is the shading. The tail can use a little more dark shade, the body can use some more shading, and the rightleg is really off. Try looking at a reference when shading your sprites.
Also, i would reccomend that if your new to revamping, try doing some some Gold and silver ones before going to red/blue. They are simpler to do, and they dont need as many edits.

 

[Black]

well..........It's ok but like OmegaDragon said it need's better shading I cant tell you much else

 

[Tiemen.M]

ok il try to make the shading better.

 

[zipzap713]

like everyone else said, work on the shading. and the thigh line u should make darker and the color of hte thigh should be a bit lighter. but other than taht good job.

 

[Manetric]

You need one more shade.