A lot of people think that men may brush-off compliments more than women do but actually, they also enjoy these compliments when they are given to them correctly. One of the compliments you can give is to show the man that you believe in him. You can tell him, “I know you can do it.” or “You have already accomplished so much. It will not be surprising if you do more.” You can also compliment men on their appearance.
They will not be too picky with what you will compliment. It can be their hands, their features, and so much more. They just want to know if they are aesthetically pleasing to you. The more you acknowledge the efforts of the man, the better he would feel.