Think through your son's accomplishments and the aspects of his personality that make you most proud. Complimenting a grown child on things that he has done or the way he has done them, will likely stick with him and make him feel recognized. If, for instance, you are very proud of your son's compassion for others, start out by telling him that. Follow up by recalling a specific instance when you saw this trait in action. Your son will feel wonderful knowing that you have paid attention to his actions, even if you never mentioned so before.

Think of the ways your son has personally impacted your life, or ways that you see yourself in him, and list them. Even if a parent-child relationship is tenuous, a grown child will appreciate hearing about a connection that he has with his parents. If your child has a particular trait that you admire but do not possess yourself, tell him how much you admire the trait in him and how you would like to learn from it. Acknowledging that your son possesses qualities that you do not lets him know that you respect him as an adult and an equal.

Select the most important ideas and begin writing your son a letter. Start the letter off by explaining that you want to express how much you love him. Then continue by telling him the traits that you admire and where you see these traits in his actions and personality.

Decide if you want to send the letter, or if you'd like to express the feelings you have written down face to face. Either way, having written out your thoughts will make the exchange much easier and clearer. While a face-to-face exchange can create a wonderful memory, a letter is a tangible object that your son can come back to and read again when he's feeling low, or needs some encouragement. When deciding on your method of delivery, consider your relationship with your son and the way you best communicate.

Send the letter, or set up a lunch date in a comfortable restaurant where you can talk freely with your son.