Leather shoes require a certain amount of tender loving care. Often, new leather shoes arrive hard, making for an uncomfortable wearing experience. Even old leather shoes can harden. There is plenty of information out there about how to make leather shoes soft--some would say too much information. To make things simpler for you, here is a simple guide for softening leather shoes.
As soon as you purchase a pair of leather shoes, rub them all over with saddle soap, both inside and out. Leave no residue. Make sure the cloth you are using is made of cotton. A soft-bristled shoe brush can work wonders too, and will help to work the saddle soap into the leather.
Sometimes only a certain part of the shoe will be too hard or pinch your foot in only certain places. To make leather shoes softer in only certain areas, soak a cotton ball in 70% isopropyl alcohol solution and then wring it out. Dab the cotton swab wherever your shoes need softening. Then tightly stuff your leather shoes with newspaper and let stand at room temperature for two days.
To keep your leather shoes soft, condition them with a leather conditioner and then apply a sealant. This will prevent water from invading the leather through its pores, in turn slowing the hardening process over time. Repeat as often as needed.
Another trick to keeping leather shoes soft after you have treated them as in Steps 1 through 3 is to wipe out your leather shoes inside and out after each use. Sweat and salt can infiltrate your leather, breaking down the leather and stitching, compromising the softness.