To begin the process of choosing the correct shoe for you, it's important to know what foot type you are.

The shape of the sole of the shoe, also known as the last, should be paired both with your foot type and with your needs in a shoe.
Running shoes can come in a straight last, semi-curved last, or curved last.

A.  This is the imprint of a "normal" or average foot.  Note: The area that is not weight-bearing is where your foot arch is located.  Having this is important to foot function, both providing shock absorption and leverage to the foot.

B.  If you have a flat foot, the sole of your foot is almost entirely making ground contact and you lack the adequate leverage your foot needs for propulsion.

C.  A high-arched foot tends to have more pressure on the outer edge of the foot, and therefore the pressures are not evenly distributed.  This foot type also lacks the adequate amount of shock absorption needed in the foot to function correctly.  Because of this, pressure will move higher up in the body to joints that will absorb the shock and can cause pain (E.g. Your knees).