I found a series of Jonathan Williamson's (montagestudio dot org) tutorials on modeling Foot, Hands, Torso, incredibly educational.
Here's how I went about making the intersection where the toes had more edges than the heel part of foot. I show this in a simple example where one edge needed to flow into three edges.
Here is the demo tutorial video I made.
Also Checkout Zeth Willie's (williework dot blogspot dot com) excellent tutorial videos on making an articulation friendly edge flow for the knee. I used the technique he describes when I was making a toe nail of a foot.
Checkout Brian Tindall's (hippydrome dot com) work on hand/arm proportions: very inspirational. I applied the proportion guidelines he demonstrates by wire frames of the hand when I was modeling my hand.