When he's talking to you, really listen to what he's saying. Don't interrupt, don't offer advice unless he asks for it, and just be there for him.
Let him know that you're there for him, no matter what. Encourage him to pursue his dreams and goals, and be his biggest cheerleader.
Physical touch is a great way to show your love and affection. Give him hugs, kisses, and cuddles, and let him know how much you care.
Share your thoughts and feelings with him, and be honest about your needs and wants. This will help him to get to know you on a deeper level and trust you more.
Don't try to be someone you're not just to please him. Be yourself, and let him love the real you.
Spend time together doing things that you both love.
Show him that you care about the people who are important to him.
Everyone makes mistakes. If he does something wrong, be willing to forgive him.