Be observant and thoughtful with little things and even do chores that the other dislikes.
Figure out what communicates love to each other and do that.
Even so, the advice has stuck in my head all these years, and I still recite it to single friends who seem to have trouble making romantic relationships stick.
The point is not that you should act arrogantly or as if entitled, but that, if you act as if you have value in the world, others are more likely to treat you that way.
He told me that when a married couple fights, no one wins.
This advice has helped me realize that if I fight with my husband, getting in little digs doesn't matter, because it hurts us both.