Use a bristle brush or clean cloth to scrub any dust or dirt away.
Apply shoe polish at least once a month (and more often if you wear these shoes on a daily basis) to protect the leather against water, revive its color and give it a clean shine.
When the leather starts to look dry and cracks start to form, use a leather conditioner to restore the leather natural moisture in depth. This can also be prevented by applying more often a leather cream.
Use shoe trees when storing your shoes, it will absorb the daily moisture from the inside and preserve the shape of your shoes over time.