(I believe these are out of print, and the author has since passed away) This book called "Successful Drawing" is by Andrew Loomis, and it discusses this very issue in... well, boggling detail. It starts talking about figures at page 67 [link]
It's a bit dense, and harder to consume than a tutorial, but highly informative. Knowledge of general perspective is obviously required (The books is chocked full of perspective instruction!)
"Figure Drawing for All It's Worth", by the same author, also goes into this topic in a more elementary fashion, beginning on page 34. There is an amusing series of drawings on page 35 dealing with placing characters within a scene. [link]
Any tutorials on this?