In any relationship, the more you know each other, the better you get connected to each other. The best way to each other's heart is to know about each other's childhood, those days, those memories, the things they liked, the days they struggled, the games they played and hence the after-math happened at home etc. Once you know each other's pure thoughts of those younger years, it's easy to make them feel happy at number of occasions. It varies from person to person what they prefer of all those memories from earlier days. That's what is up to their partner to find out and hence to act. I believe this is certainly a way to strengthen the bond as well as to keep it going for long.
You may try!