Pretty good start. I have a few comments and suggestions.
Lighting is hurting this image the most. Did you use a GI Dome?
In this case, it gives the scene a flat appearance, lacking contrast.
Take a look at Carles Piles’s Environment: Lizard & Bug thread on CG Talk.
You can take some cues on how to set up your lighting (if you plan to tweak your render at all). I’m not saying to duplicate his work, just examine his techniques.
I would like this image better if you modeled the clouds in Blender vs. using a background image. Also, try making your rocks/clifs a little more detailed.
Lastly, I would like to see you tweak your textures some.
Good work overall. Organic modeling is not easy. I like the Gecko.