err, i dont really have any 'official' learning resources. i'm self taught for the most part, though i've picked up a lot of tips from the tigsource populace.
for the most part, i just look at the work of good artists (kinnas), start to feel shitty about myself (curse you for being so fucking good ;-;), and then look at pictures of women whilst weeping silently. something decent comes out eventually.
sometimes i use references, sometimes i don't, but the process is the same: draw an oval, determine the direction it's facing, and mark out the general area of where things should be. it used to be that i would start by drawing the eyes, or the jaw, but mapping everything out first makes things infinitely easier, and helps to combat facial distortion. it also helps you think in a 3d space. its useful to know a little bit of bone structure (though this is something i need to work on). after i get the map down, i work on the lineart, making sure to use a different photoshop layer for each feature, so that if something looks weird, i can manipulate it independently of the rest of the lineart. then i use a separate layer for color (which i use sparsely not out of any sense of aesthetic cleanliness, but because i cant color skin for shit). afterwards, i tweak the shit out of everything.
im not the greatest artist, but im learning, and at any rate i hope this helps you on your quest for GREAT JUSTICE