I start with a quick sketch, using a series of points and lines. i use a ratio from the original subject to fit the canvas. After painful measuring and to make sure the drawing is correct and accurate. I can plot out the values. this first sketch is the most essential part of any accurate artwork.
Next I plot out the different values, this should just be basic plotting of different values from darkest to lightest. you will have to make sure that the shapes you are filling are accurate. this is another essential part of the drawing, I make sure that the drawing and value areas are perfect before i move onto the next step. If these stages are wrong at all the drawing will not be right.
I usually start from the outside in, growing tighter and tighter the closer i get to the focal point. in this case i am putting the focus on the deer's head. at this point i dont want to get too detailed but want to focus on value first and hue second