Anyone can be beautiful. It's not about the clothing, the hair, the make-up. It's about the way your smile radiates warmth, or dancing when you're excited, no matter who's watching. How to be beautiful? There are no guidelines, and anyone who tells you otherwise is telling you how to be pretty. Pretty and beautiful are not synonyms. Pretty is a but an adjective, whereas beautiful is so much more. Beautiful is a sunset, or the rain, or being in love. Beautiful is singing in the shower, running at night, and laughing out-loud. Beautiful is the way a flower smells, or the feel of their skin. I'm sorry if you disagree, but this is the best I could describe such a, well, beautiful word.
An appropriate response:
"I love you too."