Low poly anatomy modeling

   3D modeling is something i have been able to do with relative ease. But looking back at my gladiator I've realized that there are many many mistakes within it. Of course i didn't expect to make a perfect model first time, I don't expect to be making perfect models in years to come. But what i do want is to be able to make one that has a good understanding of the human form with good proportions, while keeping a relatively low tri count. So where do i start?
   The recent summer project has got me thinking more about making a more anatomically correct model this time, compared to my shambles of a gladiator i did back in march. I intend to concentrating on where the muscles and bones are more prominent this time. I think the amount of life drawing poses I've done over the summer has helped me understand the human form a lot more. So when i came to make start my survivor I expected to get cracking straight away without too many problems. But i find myself just sat here thinking, how do i get from here to there?
 

   This is my gladiator mesh. I've come to realize that its too linear, it needs to be more rounded and have flowing edges rather than being quite boxy.
  My character will be pretty skinny so he wont have a lot of bulky muscle definition, but on the other hand he will be malnourished and underweight so he will have some defining muscle mass, like the deltoids. Along with this his stomach will be receding in slightly to show the lack of food he's had. Most of this can be shown through the textures alone.
   All this is well and good but back to my original question, where do i start? I guess i'll have to make some mistakes and find out myself.