I can not seem to get a good photo across this entire piece. One side is always over or under lit. In this case, the right side is blown out a bit with glare from light coming from a window across the room. The lower right cactus actually has far more range of color. The smaller detail image is a closer resemblance to the actual. Anyway, I have worked on this piece for quite a while, never feeling good about it, something always bothering me so I let it sit for a while then came back to it with a clear understanding of what I didn't like about it and why. I proceeded to repaint those areas until I was satisfied with each area. Seeing it small always makes me see other things I don't like but other than a few minor adjustments here and there it is now pretty much complete.
UPDATE: New photo, much better