with a very sharp point, and extremely light pressure, I move the pencil point in a circular (sometimes almost elliptical) motion, slightly overlapping as I move along. this technique allows maximum control of the pencil, and creates the smoothest finish, but is oh, so slow.  the advantage is that you can get extremely subtle blending of color. I use the brillo pad method for the face and hair on all my portrait commissions.

what is the vertical line technique?

vertical line is simply that.a vertical line.next to another vertical line.next to another. the length of the line is usually determined by the space it is filling. a large space can take a longer line than a small space. as you work in vertical line, you will notice that there is some overlapping. since working in colored pencil means building up color with layer after layer of pencil, in subsequent layers, you can straddle that overlapped area. you can also minimize the overlap by using a very light touch.

using a sharp instrument to indent the paper surface. when you then cover the area with pencil, the impression made with the sharp object will not fill and will show up as white. use this technique for little wisps of hair around the face that are lit by sunlight, cat whiskers, and white hair in darker colored beards/mustaches.