The start point for pet portrait drawings

I’ve been told on many occasion “I just wouldn’t know where to start”, when someone comments on my pet portrait drawings. Well the truth of it is I mainly start at the top and work down. The reason for this is so as not to drag my hand over the work I’ve just done. I do still use an extra piece of paper played over the main drawing to stop smudging, but as best practice I start as near to the top as possible

drawing startpoint