Fit the larger of your feet as feet are not the same size. Trim your toenails straight across slightly longer than the tips of your toes. If you have problems with your feet, have a professional podiatrist take care of them. Most people are born without foot problems. Corns and calluses are caused by friction and pressure from skin rubbing on bony areas when wearing shoes.
Calluses are nature's way of protecting sensitive areas of the foot.
These are the least treated foot problems and therefore continue to be problematic. As a person's income increases, foot problems decrease. This is the best exercise for your feet. Park away from the nearest entrance at the mall. Don't watch life lying down.