Follow these basics to find shoes that fit, feel comfortable and help you avoid injuries:
Athletic shoes tend to run shorter than dress shoes. Your walking shoe will likely be 1 to 1-1/2 sizes bigger than your other shoes.
If your heel rolls inward when you step (called "overpronation"), or if you have a high arch, get a shoe with plenty of arch support or buy arch supports that you can insert into the shoe.
Running shoes often have a raised heel to meet the motion needs of a running stride. Walkers don't need that. Look at the sole under the ball of the foot and choose a shoe with the least height difference.
Buy new shoes every 500 miles. Once you reach that milestone, the shoe materials have broken down — even if you can't see it with the naked eye. Continuing to use the shoes can lead to injuries such as shin splints.