What a cute little guy this is. I see one of his feet already has turned the shade of the leaf. Wonder if, after sitting a longer time, the rest of him would change? And actually, it probably would have been a better idea to wait until he resembled the leaf a bit more before posing him for DPC. But you worked with what you had.
Now, I see you have the kit lens with your 300dRebel, and that's really a good lens and it should have given you a sharper image. But the lighting conditions may have been just too low for it. 1/60th of a second @ 5.6 is a long time for creature shots, and unfortunately, it shows in this image. If you have a tripod, that may help if you are in similar conditions in the future. Or move the crreature to a better lighted spot.
Your subject is quite well posed in the frame; I'd give his nose just a touch more space so he doesn't look hemmed in. YOu did have comments about your border. I try not to look at borders, as they tend to distract, but this one really is a bit bright. Perhaps one of the very dark greens would look good as a (thinner) border... Just a thought.
I'm so glad you found DPC and are learning so much from it. And I expect you will reach your goals before you know it! Good luck.
The picture is cool, but you have exposed too long and the lizard moved. I would have increased the ISO number till you have less than 1/200 s exposure time. Noise is not an issue at 640 pixel size.