EDIT July 22 2012:
Some people are confused about the lineart and what happens to it here. All I did before that was 'fill' the lineart after selecting it with the magic wand tool. Once filled, I kinda work underneath the lineart and create a clipping mask above the fill layer-I get all my basic stuff done in this time. Then once I'm ready to start cleaning stuff up and blending the lineart-I simply merge the lineart with the fill layer and start working over it.
Clipping masks are my best friend when it comes to keeping things clean and 100% opacity (as the layer below is 100% opacity, and the clipping mask stays within those boundaries.)
Sometimes I keep my lineart if it's really clean, sometimes I don't. Other times I just sketch something out and run with it.
This isn't really a tutorial, but hopefully it can break down how I work...basically. The first few steps go by quickly (minus the lineart, which I rarely do because of the time it takes), but when detailing starts coming in it gradually takes almost twice as long as the step before. Detail makes up about 80% or so of drawing time.
I use the default PS brushes and a triangle shaped brush and use the brush settings pallet, opacity and flow with each brush depending on how I want the brush to behave.