Trace or draw the subject. Put in as much detail as you need. If you traced it, use the same printout and cut out the subject along the trace lines, not the image lines. This will make sure you match the lines on the substrate. Now fill in the background. I use magnets to hold down the mask. If you want sharper lines, normally close to the focus point, place the magnets closer to the edge and for softer edges place them further in. I started doing the darkests parts which were the outlines of the scale and the eye. I actually uses frisket to keep the highlight on the eye clean. I then decided to rather do them scale by scale and the outline of each scale as I move along. I then got second thoughts about the way I was doing this so I added colour to see if it would work. And yes it did. I then just continued filling in scale by scale keeping the light areas as light as posible. Where I had to, I used erasers to get back the whites. Doing the out of focus areas was not as critical as the infocus parts. Values were darker and edges were softer. Back to the infocus bits and a lot of light lines and erasing.