How to draw busts of sculpts on paper? Write your method with photos!

Hi there. I love drawing something on paper, but I still don’t understanding how to compositing proportion before drawing bust of sculpts/busts. This is what I did in my free-time:https://scontent-b-ams.xx.fbcdn.net/hphotos-xap1/t31.0-8/885284_479407182125068_84516098_o.jpgIt token above 5-6 hour and late. Drawed from real photo which I found from Facebook’s users photos. So, problem in compositing on A3 paper when drawing busts of real sculpts. And I really want if somebody teach me how to do that with screens/videos (step by step). And if you don’t understand me, I meant like this:http://portal-1.ru/arxit/images/ris157.gifThanks in advance!