Set up a routine, such as Sunday dinners at her place or making first Fridays of the month a family movie night. If she lives farther away, plan a family trip at least once or twice a year, if possible, to make sure you spend some time with her. In psychology, there is something called the "mere-exposure effect," which refers to when individuals have a preference for certain people or things for the simple reason that they are familiar to them. Setting up routine visits and meetings can help cultivate this.