I try to simplify the colors I see and roughly map stuff out using those few colors; trying to keep it clean-looking at first by using very opaque strokes. If a color I already have in my "palette" won't work for a certain area I'll make a new color, but I try not to blend stuff together until later into the painting.
Basically I try to plan out all the colors I'll use from the start, I'm still not great at it but am getting better. If I need to have a slightly different value somewhere else later, I'll take one of my colors and apply it with some transparency. I never use a blending tool, actually. I just work in varying transparencies. My brush is set to be more transparent the more pressure is applied.
Kind of difficult for me to explain it since I don't ever really think about it in such a way, so I hope I at least made SOME sense .