Learn what type of foot you have
The feet can be classified into 3 categories based on the curvature of the arch they have. To determine the type of arch you have, you can wet your foot and then step on a piece of cardboard.
If the imprint of your foot is like the first image, then you have a medium/normal arch.
If the imprint of your foot in the middle is thinner, like in the middle image, then you have a high arch.
If the imprint in the middle of your foot is wider, then your arch is low (the foot almost touches the ground, flat feet).
The arch of the foot, as well as other factors (e.g. weight), affect the way you walk/pronate. By observing where your old shoes wear out the most, you can easily determine if you have:
Neutral pronation: wear on the area below the outside of the heel and below the big toe (often neutral arch).
Underpronation: greater wear on the outer area of the sole (high arch).
Overpronation: greater wear on the inner area of the sole (low arch).