Shoe Fitting Pointers

When trying on shoes, make sure you're wearing the appropriate sock. For instance, if you're trying on boots that you'd wear with heavy socks, don't try them on with thin nylons and vice versa.
The best time to try on shoes is usually at the end of the day. Most feet swell slightly as the day progresses. However, don't abuse this rule of thumb: if you've just completed a sightseeing tour which required 10 miles of walking, and that's not your typical exercise routine, then by all means don't try on dress shoes that night! The point of waiting until the end of the day is to make sure that the footwear can fit you at your widest-- kind of a "worst case scenario" check. If your feet swell abnormally, it is recommended you try on shoes when your feet are at their most swollen, and go to a shoe store that has a Certified Pedorthist on staff for expert fitting.
No two feet are exactly alike, one is usually bigger than the other. The first shoe you should try on should be the one for your larger foot. Even though there are about 20 separate parts to an average shoe, the fact remains that they are mass-produced. It's up to you to alter the fit. Refer to the Shoe Fitting Reference Guide for information on how to alter your shoes for a better fit, or a shoe store with a Certified Pedorthist on staff can help you with this process.
Put on both shoes. Stand up with the shoes on. Walk around a bit. You should be able to wiggle your toes in the front of the shoe. For most footwear, your toes will be able to touch the upper of the shoe, but there should be 3/8" to 1/2" of space between your longest toe and the end of the shoe. The longest toe is not always the big toe. Refer to the Shoe Fitting Reference Guide for visual reference of proper foot placement within the shoe.
Don't buy shoes that are too tight. If you're at the point where you're praying they will stretch to be comfortable, they probably won't. It's true that soft leather and suede give slightly, molding to your foot, but they will not dramatically increase in width or length. There's a difference between a "snug", comfortable fit and a "tight", uncomfortable fit. A few laps around the room should help you decide how they feel. Refer to the Shoe Fitting Reference Guide for proper fitting instructions.