disclaimer-ish...I like writing down things I have sorta "figured out" over the years, and some people seem to find it helpful, but this isn't the word of god and I'm sure a lot of much smarter people have given better over the years, so please understand that this is just my personal experience/opinion speaking and nothing else.
second disclaimer: as I said in the tutorial, this is aimed at strictly cartoony styles, NOT REALISM. I realize there is sometimes a boob-space in real life. My argument is that a cartoony style with lines requires some realism sacrifices in order to draw your attention to more important things, like gesture and shape.
Also I drew the examples in like 10 seconds so.. sorry, they're not the best, haha. PIIIINK
anyway, these are all things I would have liked to know about 5 years ago, so that's why I wrote this. (I'm looking through my old art. YEEP! it's scarier than that ghost I saw the other day.)