Polygonal personality...

I've been struggling with this; how do I make a virtual character look like they're fit to be a member of the human race? I mean, I can move the vertices around, I can extrude parts of her face until my heart's content, but where is her 'life'? What defines her as someone that would not look out of place walking down the streets of any town.

Proportions have a lot to do with it, as do the finishing touches of skin, hair and as we all know the eyes are of major importance. I could texture her lime green and give her a moustache but as long as I get the eyes right I'm 90% of the way there. But what of the other 10%? This is my quandary...
I've made sure she is built in an efficient manner (there are no triangles on her face and only a couple of them up on there top of her head) as this will help not only with adjusting the mesh while modeling but also it's invaluable to get it right for skinning* and animation.
I've researched faces and heads and got myself some decent reference.
I've spoken to friends and work-mates about their experience of modeling characters.

I'd better leave for work. I'll continue this later.

I've made some minor tweaks to Elles head; namely I've softened down the SSS effect so her nose is no longer so 'fleshy' and transparent. I've also been messing around with the area around her lips, especially her top lip as a few people had commented that it was not right. Oh, and I've fixed her forehead so that she's no longer got that 'Klingon thang' going on.

*Skinning is what we do in order for the various parts of a model to be manipulated and animated. In this case her face would be mapped onto a series of 'bones' and the vertices assigned (or weighted) to each bone. When the bone is then translated or rotated the weighted vertices are influenced and move with it.
I should really write a jargon buster for some of the terms I use.