In the setting up phase for the project, you have to define equivalent points on everyones faces, ie, left corner of left eye on person A to left corner of left eye on person B. I learned some rather interesting things about faces in the process.
The problem with starting your people drawing education with anime/manga characters is they all look pretty much the same, except for some maybe stylistic differences in eyes/hair, etc. But the overall face structure amongst main characters doesn't vary much. Not true for real people. All the details i consider standard vary from person to person. For example, some people have a flat bottom eye (i think perhaps this is true of most asians but i suspect people would find it weird if i started starring at their eyes for lengthy periods of time). Some have a rounder structure.
It's a great exercise to take a bunch of people's portraits and try to map the outlines of their features to each other.
I felt inspired to do a little face sketching afterwards so here's a doodle of my friend sharon:
2/10/2013
dont know why i didn't post this before
http://www.youtube.com/watch?v=da8ZlfRA4xA&feature=player_embedded
a video of the morph of sharon to me