Well, you could have a little smile in the eyes to convey positivity. I like to turn it into a learning experience for myself while giving a compliment. “I love your outfit, where did you get it? I love what you did with your hair, where do you get it styled/how did you learn to do it? Any advice on how you achieve that makeup look?” Or I just sometimes give a genuine, heartfelt compliment. “Your hair is gorgeous and I love that colour on you!” Just be genuine. The intent will be there. :3