Doesn't look half bad, really. Though I'm wondering where his left leg (far to perspective) is coming from at that point... :-) Besides that, the pose looks good.

And the chair... well... yeah, you admitted the chair's perspective looks wrong, so... yeah. :-) It might work better if you try to draw the lizard sinking into the chair a bit... add a bit of depth and softness to the chair, or a bit of "squishiness" to the lizard's back (Like... hide the spikes on his back). That might help for later.

Don't fret too much over shading, I say. It takes time, usually. Though I do like the shine on the lizard's belly.

All in all, not bad. Keep working at it! NOW! GO! :-)