First of all a couple of warm ups.
I started by drawing a loomis skull from memory (and failed bad :P), so I then went back to Loomis and studied some of the basic head designs again. Maybe I am just incredibly slow or stupid, but I need to really go back and forth until the information is truly absorbed. So expects heads for at least another month before I move on to another part of the body.
Now... I just wanted to share my thoughts on "copying" and "drawing form masters". When I was a kid I NEVER copied anything. I thought that because I was a human being, and an obvious talent in drawing, the knowledge of human form would come to me naturally..since I am myself a human.
Then I started to think I was just a crap artist since it wasn't coming to me, and I stopped drawing for a while (a few times in my life actually). The thing is that "knowledge" does not come to a person naturally. A doctor is not born with that knowledge and neither is an accountant, information/facts need to be studies.
What does come natural is your desire to draw and some people will probably be more adept at the act of drawing/painting than others. But everybody has to learn anatomy. Most of the really awesome talented (young) people, copied their favorite cartoons and comics all the time. They might not even need to study anatomy, because they already learned the "shortcuts", the shortcuts the other artists have developed for suggested form/anatomy.
Case and point, check out the first cave drawings...hardly the stuff you see in a disney film or canvas! Or those renaisance painters. Check out those faces and proportions...that's not what a human looks like, but it is what every other painting at the time looked like. They all learned from their masters and the great artists put their own spin on things, but knowledge was obtained through copying their masters.
So anyway, if you are an obnoxious kid like I was, put that pride aside and start copying everything you think looks interesting. You'll thank me for it when you're awesome :D