Put your bare foot on a piece of paper and trace its outline. Take the foot tracing when you go shoe shopping. Put the shoe you are considering buying on the tracing. If any part of the shoe is narrower than the outline, you can be sure the shoe will not fit your foot properly. It is also important to match the shape of the shoe to the shape of your foot.
Some shoes have fairly straight lines.
Others have curved ones. To check the shape of a shoe, look at the sole and compare it to the tracing of your foot. If your foot tends to curve, but the shoe is straight, you need to try another shoe. Try to find shoes that have the same shape as your foot. It should not rub up and down on the heel.