1)I generally grid a series of horizontal and vertical lines on the reference picture to get the proportions correct (a very old trick) 2)Sketch out a rough idea of the character's general shape, features and shadows... 3)Keep refining the drawing until it looks finished
I use a mechanical pencil (to maintain the sharpness) w/ HB o.7 mm lead and Q-Tips to blend tight areas...
oh yeah, take your time these pictures take about 8 to 15 hours to do right