To add to what RANDO said, I always start making (carving?) hair at the bottom. Meaning, if it is a beard that you are carving, then start making the cuts at the bottom of the beard and work your way up . This allows you to make overlapping cuts or layered hair.
Look at your own hair in a mirror and you'll see what I mean. The longer hair is down by your coller and the shorter hair is on top. The shorter hair lays OVER the longer hair. Therefore you carve the long hair (at the bottom) first.
I hope you understand what I'm saying (I'm even confusing myself a little).
Study any and all pictures that you can find, go to the art gallery, and even observe other peoples hair and keep trying, you'll get it eventually
