This is a nice composition. Its got great light and dark contrast. I'm assuming you're using the dodge and burn tool? If so, you did a good job with this, but be aware of over-using it. Dodge and Burn will not give you that same range of realistic colors. For best environmental effect, try picking your own colors. I like to reference from photos, to try and capture that realism.
My biggest issue is the lack of color. You have this really neat creature in a sea of green and white. While I see what you were going for, dont limit your palette! Sunlight is rarely just pure white. A bit of yellow to this would not only have brightened it up more realistically but would have given you a complimentary comparison for your flower! (purple and yellow, opposite of the color wheel- complimentary)
Your design is cool, and seemingly pretty thought out. (I dont know if this is a creature from something else? Or your own?) Also be careful of using the smudge tool. While a lot of this lighting could be soft, you have a pretty hard light source coming from the left, which would create hard shadows and hard highlighting.
I think you're on an awesome path and should keep going. I look forward to seeing more of your work.