I'm working on a new piece for my November P.U.M.M.E.L. match. I picked the theme this time, and I decided on Legend of Korra. I was watching this season, and thought the fire and water effects would be a good way to jump into a more painterly technique. Usually, I sketch, ink, and color with either flats, like in Rob and Elliot, or 1-2 levels of shading/highlights with gradients like in my Storm/Black Panther illustration. I wanted to try out Photoshop CS6's new realistic paintbrushes, and this seemed like as good a chance as any.
I started off with a pencil tool sketch.
After that I blocked off the flat colors. I changed her legs to a running stride, and started working on the water distortion. The water effect is on a separate layer with the mode set to overlay. For water distortion, you can create a refraction effect by shifting the image behind the water by an even amount. I moved it a little bit down and to the left. I then added undulations in the outline with displaced spots. I left the fire as a block color for now. I started painting her face to get an idea on how I wanted the water to reflect back up onto the underside of Korra's face. Since light bounces off and passes through the water, it casts more reflected light than an opaque object, so the dominating reflective colors are going to be from the fire and the water on either side of her body.
Here I added most of the shading with the Flat Curve Think Stiff Bristles brush in PS with the opacity set to pressure sensitive. I picked a main light source (top-left) and visualized the objects in 3D space while adding volume with shadows and reflective lightsources. I added the water and fire reflective light with an overlay layer. The fire effect is created by building up layers of flame-like shapes progressing from orange to yellow to white. Remember that the white part is the hottest, so it should be prominent only where the flame is thickest.
Here I added Naga, and made some corrections to Korra. You'll notice how Naga has the reflected light sources on him as well (overlay layer with a radial gradient). I also moved the fire to intersect with the water stream and added distortion effects and a glow (overlay gradient again). I made sure to use a large size brush with more visible bristle strokes on Naga to get a fur effect.
I'm still in progress, but here's a zoomed in view of the fire and water effects to give you a better idea of how I achieved them. I still need to add the distortion to naga, but since I'm not 100% sure about the placement, I haven't implemented it yet.