Thanks both of you for your quick and constructive replies.
Progress Update:
First I fixed the back end of the carrot (you both were right. It was odd). I tried using a more yellow hue for highlights and added more shadow using purple hues. I also tried staying away from dithering too much, however, I think it looks good on the leafy green area.
Good idea, or bad?
So here's the newest version (top) compared to the very first one (bottom).

I can totally see an improvement.
Thanks, and again - Are there any techniques that I am using incorrectly here? Steps I can take to improve?
I'll start working on my next practice piece soon.
-Mag