@ChrisConnor Nice! Love the concept. Per what Larue is saying, I think I'd move her up or down slightly to avoid that tangent with the hand/lip that's smack in the middle of the piece 
2 things I might consider playing with...
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I think the bubbles are throwing the scale off... it's not entirely clear what is making the bubbles of what they're coming off of. We have some foreground bubbles that are blurred and the same size as some of the background bubbles. I think you could really emphasize the scale by making it super clear the mermaid is giving off tiny bubbles and the dragon is expelling huge bubbles.
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This is an awesome piece to mess with the lighting to really pull the viewer into the focal point. This is super rough but I just played with some values to separate the value ranges to try and bring the focus right in the middle and keep the mermaid the highest contrast level on that rim lighting. Might not be at all where you want to go with it, so certainly take any advice with a grain of salt.
