Try to do it at an unusual time. Most girls have been told they're beautiful when they're all dressed up for a night out. Try telling her she's beautiful just after she's come back from the gym, or when she's not wearing any make-up. It'll feel more meaningful and sincere.
Simply telling a girl that she's beautiful can certainly be flattering, but there may also be greater compliments a person can bestow with their words. Rather than simply telling a person that they're beautiful, mention smaller aspects of their beauty, such as their smile or behavior, that you are attracted to.
Complimenting a girl over text can be a great way to let her know you're thinking and appreciate her. However, being thoughtful and respectful is essential when complimenting a girl's appearance over text. When telling a girl she's beautiful, it's critical to do so genuinely and not to objectify.
In sum, it is always appropriate to tell your wife/girlfriend/significant other that she is hot but best to avoid saying it to anyone else. The hot ones know they're hot so you're not telling them anything they don't already know anyway. But you can think it all you want!
Say, "You're beautiful," or "You are exquisite." Try picking out one particular quality to compliment her on: say, "You have the most gorgeous eyes," or "Your smile is radiant." Don't be afraid to get creative and tap into your feelings, and make sure that you mean it.
Since you two just met, compliment something you notice about her, like her laugh or her jacket. Stay away from anything too physical, though, or you could come off as creepy. Some good compliments include: “You have an amazing laugh.”
Calling someone beautiful can be flirting. It's not always a romantic comment. A guy will often comment on a girl's beauty because he's attracted to her. In short, it's all about intent.
The main difference is that while the word pretty is used to describe the outward appearance of a person, the word attractive has a wider scope, which ranges from appearance to personality. Also, while the word pretty suggests appeal in a delicate manner, attractive suggests appeal in a sexual manner.
Without being cheesy, throw some nice compliments her way. A good compliment must be honest and genuine. Studies show that a personality-centric compliment works much better than a compliment relating to looks or skills. If you think she has a great sense of humor, tell her.