Honestly Jon this looks amazing. My only critique would be to render the leaves more. Maybe use a brush that has a jitter to create some more randomness that you could work with, right now they are all in the same direction and just look like your value pass. Give at least one leaf that can show us what the shape of these leaves would be, with a clear distinct textural highlight on the edge, and then blend out the rest. That would be my recommendation.
Great first pass. Good composition, interesting overall color, lighting, atmosphere, and textural indication. Be careful not to let the extreme foreground shapes (lower right corner) draw the viewer too much (with edges too sharp, shapes too dramatic/triangular, etc). If you show some subtle light curving over the edge of the foreground objects it can help soften that contrast while also showing volume. Check out how Dylan Cole handles foreground devices like that: http://www.dylancolestudio.com. Even though his style is really photorealistic, you can borrow the principle and apply it to more stylized compositions. Also study "broken color" (http://www.creativeglossary.com/color/broken-color.html). Incorporating a bit of it in your painting process can help really enrich the sense of texture while retaining a painterly feel on your final pass.
really great textures and movement in the trees. I love the mood of this piece, the trees are quite menacing, great job on that. You've also got a great illusion of distance with those blue fading shapes. The airbrush glow you've got is a bit distracting, it feels more like a fog than a glow. Try shrinking its influence, or changing the layer mode of the glow to Overlay (that may make the background crystals stand out too much, you may need to have their glows on separate layers). Actually, here's a random tutorial you can try out: https://www.pinterest.com/pin/AUTe4hZCndWGQq18j31OTmo0ihUANMoA15tpgqMGJnWajU-80dqv_do/Or, you could try painting in the glow effect with a white/blue Overlay layer directly onto the base of the crystals, to give an internal glow effect. Here's and example of what i mean: https://www.pinterest.com/pin/363595369896922692/ (sorry it's in Chinese) Also, just for fun, check out this crystal painting tutorial i found: https://www.pinterest.com/pin/478507529139937643/Hope that helps, great job!
Awesome piece Jon! I think the trees are working really well (especially in the foreground) and the overall composition is very strong. I agree with the comments above about the leaves and glow for the crystals. I think that a little more saturation in the crystals could give this a really awesome feeling as right now it's mostly not very saturated at all.
The painted texture on the trees is very well done. And your overall composition and value structure reads well from a distance. I'm not sure what the shape on the top is suppose to be, I assume its the leaves of the trees? So giving the viewer more clues about what that material is would be helpful.