Generally it is good to clean your leather case with a moist cloth, but don't over do it. Be sure to have your phone in when taking care of your case so you don't squeeze it to much.
To better protect the leather you can use a leather moisturiser. Also good leather care product is a general classic hand creme. Just a bit so the leather gets its flexibility back.
Don't squeeze your Calypso Case.
Don't throw it around.
Don't put it in you back pants pocket. Both the case and your pants will thank you.
Don't sit on it.
Don't expose it to direct sun.
Don't spill water on it.