Some general tips:
- Fit the shoe to your longest toe, which is often your second toe.
- Shoes should be comfortable when you first try them on. Don't buy shoes and plan to "break them in" by wearing them.
- Take the same socks you'll use for jogging. They should fit well, be made without seams, which could cause irritation to the foot. If you use extra-thick socks while running, select shoes with enough room. Socks should be made mostly out of synthetic materials which "wick" moisture away from the foot. This reduces the chance of developing blisters
- The shoe should grip your heel firmly.
- While the shoe is on your foot, you should be able to wiggle all your toes.
- You should have at least 1/4 inch of space beyond your longest toe.
- Have at least 2 pairs of shoes to rotate while allowing the other pair to air out.
Weight, foot structure, and running regimen are all deciding factors. Be mindful that all shoes have a different shape, and sizes and widths are not uniform from shoe to shoe. Consider whether a special insert, orthotics, will be placed in your shoe, and whether your running style is flat-footed or on the balls of the feet. Shoes should provide cushioning for shock absorption, and ought to be able to fully bend at the ball of the foot area.