Building a deep friendship in a relationship involves shared humor, acceptance of your partner, reassurance, and building a life together with meaning, purpose, adventure, and play. It is about being friends, staying close, expressing affection, and maintaining a strong connection by telling each other 'I love you' every day. It is not just about conflict resolution but also about creating a foundation of trust and commitment. This deep friendship and appreciation for each other are essential for a strong and lasting relationship, going beyond mere tips and tricks.