The shading
To add just a little more depth to Nammers here I created a
new layer, on top of the color, but below the sketch. The sketch
needs to remail on top, remember. This layer for shading must
be on top of the coloration because I am setting it to "Multiply"
to darken the layer underneath it. I chose a tannish-grey color
to shade with, and added some extra shading to the areas that
would be darker. 
You can see to the right the differences in the
version with extra shading in comparison to the origional version.
They appear to be very dark, but keep in mind that the background
is still white.
Highlight me!
Well, usually for the highlights, I would work in two stages and two levels; one set to "screen" and one set to "color dodge", but in this case I'm going to skip the "screen" stage; to learn more about it and why I usually use it, check out the "starting from scratch" tutorial. I'm going right to the "color dodge" step because Nambroth's feathers have a dusty gold sheen to them, and I like the looks of "color dodge" for this best.
I created a new layer, this time above the sketch layer. I did thos so that the highlights would effect all of the layers. I set the highlight layer to "Color dodge".

Color dodge will create glossy, shiny looking highlights. Using
a very light tan color, I brushed in where it needed hilighting
to create even more depth to Nammers. Notice the bright, sunny-type
look this gives. Notice, also, how these two steps (extra shading
and hilighting) make the drawing look much less flat and dull.
Backgrounds!
Time to add a background! Well, only if you want to of course. Create a new layer under all of the other layers, and paint in whatever you'd like! I wanted a simple background here, so I chose some different blue hues, and painted blobs in the background. To achieve the watercolor-ish look, in the brush options, I set it to "wet edges". It takes some playing around.
But whoa! The background shows through where I don't want it to! That's because there's nothing in the rock area, and where the talons are highlighted, to block the background out. Simply go to the background layer and use the eraser tool to erase any "unwanted" background.
My rant on backgrounds: I rarely
ever color sketches anymore. Now I usually work from scratch,
which I find easier because of the way I go about it. Backgrounds
should almost always be drawn first! Why? Because you draw your
lighting and shading and mood from the background. And right now
you're saying, "Um, Nammers, you just drew the background
last on this drawing!," and you're right. Thats because it's
easiest to set up that way with this drawing, and i wanted a simple,
non-landscape background here. However, if you plan on using a
realistic background, I suggest you follow my "from scratch"
tutorial, and substitute a scanned sketch instead of a computer-drawn
one if need be. This tutorial was more or less the "quick
way of coloring a sketch decently". For more detail, to achieve
mroe realistic results, read through the other tutorial. :}
