For enjoyable and comfortable running, your shoes should fit differently to your every-day shoes. Ultimately, they should be bigger. Often this means buying a size or half size up than you're used to in order to get the fit you need. To ensure you walk out a happy customer, you need to make sure the shoe fits properly from heel to toe and that it feels comfortable with your regular running stride.
There are three things you need when looking for the right fit:
A Little Wiggle Room - You should have about a thumb's width of room between the end of your longest toe and the front of the shoe. Similar to what you look for when you're finding a good fit for your little one (something they will grow into!).
Hold It Still- Look for a secure, comfortable fit through the midfoot. Imagine a hand gently holding your foot in place. It should be snug but not tight around the sides.
The Heel Deal - There should be little or no slipping at the heel. Sometimes you might need to do one of those sneaky lace tricks to tighten this area up a bit.
It's important not to make these buying mistakes:
Buying for the looks - just because it looks good, doesn't mean it feels good!
Buying for the sale - cheap DOES NOT mean a good buy. Different brands and styles are good fits for different feet, so make sure you get something that actually supports your foot and gait rather than something that is on sale.
NOT asking for deals - many specialty stores will offer 10-20% for local clubs. At our local store offers 10% off all cleats, socks and running shoes for my brother's football club, for example. It doesn't hurt to ask!
Shopping too early in the day - Often people will go shopping early in the day, find a shoe and be done with it. However your feet swell as the day goes on, and by 4 or 5 pm, they are too small.
Now that you know what you're looking for, it's time to go out there and get a pair.