How can I prevent my feet from feeling tight by mid-day?

Assuming you spend most of the day seated, one of the best things you can do to relieve foot tension is to buy either a baseball, a softball -- even a tennis ball. Place this under your foot and slowly roll into your tender spots, applying pressure as tolerated.

This is a form or self myofascial release that will relax excited, tense tissues in your foot. You can follow this up with a calf stretch to relieve tightness in the lower leg as well. In addition, by taking your shoes off, you'll be able to extend your toes in-order to stretch the muscles of the bottom of your foot.