@benhamill as a rule it's usually better to compliment aesthetic choices the person has made rather than just what you personally like about their body etc

eg: "wow i love your top" "your hair looks great" etc

complimenting a smile is defs trickier ground, but i think there's a way to do it without being creepy! like "you have a nice smile" or "you look so happy!" is different from "you should smile more" or "that smile is sexy"

i guess in general it's about being appreciative & not objectifying. which can be tricky, especially since guys are conditioned to objectify and women are generally taught to be suspicious of compliments, but i think it's doable!