second is just substitution, trying to separate hilights, shadows, and midtones
third is my estimate of your current lighting situation, without the scales.
fourth is how I'd try to set it up.
It seems like you're using more colours than you need, and your colours aren't contrasty enough, in any case. Try to pick a distinct hilight, midtone and shadow colour for each differently-coloured bit of the dragon, then stick to those. The blue colour you're using for hilights on your greens is a bit far off from the green. Besides, why is the light making the greens cooler? Usually, your shadows are cooler and bluer, and your hilights are warmer than your base colour. It depends on the colour of the light.
Mostly the trouble with your shading is that you aren't using as much shadow as you should. I lost some shadow in the substitution, but there's not enough there in any case. Oh, and your wings are too flat. They ought to stick out more.
