I call Step Four "Go for the jugular" or in other words, go straight for the part that scares you the most, which is typically also the focal point. If I do this first, then the rest of the painting gets remarkably easier, because it's all just ancillary stuff. My focal points are also where I try to put my most saturated colors (everything else is a more grayed-out version of the color). The focal point(s) aren't usually done at this point, but it's nice to get a first layer on all of them. I'll need the other colors in the painting before I can accurately judge if it needs to be darker/lighter, if the colors are right, or if it needs more detail work to clean it up. But that all comes later. At this point, I just want them blocked in and close to the right values/colors. I try not to fill in every space exactly, cause I like seeing lines from the drawing and color from the underpainting. Starting to come together!