I like to show the impact when showing appreciation so I’ll say something like: “I felt so loved when you did X. I know it was really effortful/time-consuming so thank you.” That way I’m highlighting how it makes me feel as well as acknowledging what he put into making it happen. Other times I will focus on character traits to let him know I also appreciate him and not just things he does. Compliments are nice but ultimately they’re just evaluations and not as intimate.