Practicing gratitude is a form of mindfulness, and it can improve your mood, self-esteem, and empathy. This extends to deepening friendships as well. It feels good to be appreciated and show appreciation for others. When a friend displays kindness and thoughtfulness, try to express your gratitude for their efforts. This reassures them that you notice their contributions to the friendship. It can also boost their feelings toward the bond. You may not even need to wait for them to do something in particular. Consider random acts of gratitude that let them know how much you care and value their presence in your life.