Oooh, I like this shading technique, it has good potential.
Looks a little rough right now, but with a bit more practice I think you'll get some really nice shading this way.
Nice bit of highlight on her arm. It really helps give it a 3D look. Do that more!

Biggest thing I could suggest to improve at the moment is to work on how you do hair.
That's a nice shape of hair, but it's all exactly the same colour, and that makes it look kind of flat, and also causes the strands to all get mixed together wherever they touch.
I'd suggest choosing at least three shades of the colour you want the hair to be, so in this case, dark red, medium red and lighter red.
Start off drawing the hair using the darkest shade, then go over it and add lines of the medium shade over the top, and finally do some strands of the lighter shade.
That should help give volume and definition to the individual strands of hair.

Another thing you might like to experiment with is using small sharp pure white highlights to make things look shiny.
This is a good pic to try that one since you've got water, scaley skin, eyes and hair, all of which can sometimes be quite shiny.
If you apply just some dots or short strokes of white along the top of the ripples in the water around her foot and tail it could really bring that water to life and make it look that much wetter, and less like a sort of blue fog.

I hope all that info is of use to you. My fingers tend to get away from me and just prattle on and on when people ask for help with their art.