Start to pay more attention to the way you walk (or as we in the massage world call it, your gait). Is your heel striking the floor first or the ball of your foot? Look at the bottom of your shoes and see where you have more wear in them. Are you walking on the inner (medial) sides of your feet or more lateral? Are you standing equally on your two feet? Are you distributing your weight evenly as you walk?
Here's some good info on fee from one guy who is an amazing illustrator and another who is an awesome doctor.
From Bandha Yoga:
The Longitudinal Arches of the Feet in Yoga
In this Scientific Key we study the structure of the longitudinal arches of the feet.
First let's look at the anatomy:
On the outside of the foot, the talus, calcaneus (heel), cuboid, and lateral metatarsal bones form the lateral longitudinal arch. This is the shallower arch and is the main weight-bearing surface of the foot. Flattening and deepening of the lateral arch occurs through movement between the cuboid and the fourth and fifth metatarsal bones.
On the inside of the foot, the talus, calcaneus, navicular, cuneiform, and medial metatarsal bones form the medial longitudinal arch. This is the deeper arch. Flattening and deepening of this arch occurs through movement between the talus and the navicular bones.
The plantar fascia is a fibrous ligament-like structure that runs from the calcaneus to the bases of the toes. Lifting (extending) the toes tightens the plantar fascia and deepens the arches.
The muscles that dynamize the arches are divided into the intrinsic and extrinsic muscles of the foot. The intrinsic muscles originate from and insert onto bones within the foot. The extrinsic muscles originate from the lower leg and insert onto the bones of the foot. In this Key we study the peroneus longus and brevis and the tibialis posterior—three of the extrinsic foot muscles. Contracting the peroneus longus and brevis muscles tilts the foot outward (eversion). Engaging the tibialis posterior muscles tilts the foot inward (inversion). All three muscles can be used to strengthen and deepen the longitudinal arch of the foot.
Now, let's look at these structures in yoga postures.
The arches can be worked and strengthened in many other poses (especially the standing asanas). Gain awareness of these important structures by gently inverting and everting the feet and flexing and extending the toes in various poses. Always practice carefully and gradually build awareness as you apply your knowledge of anatomy to your practice.
Ray and Chris