So this is his favorite thing about you that is a physical trait. Enjoy!
Harry: Your hair. Harry loves to play with your hair after a long day at school, he's actually gotten quite good at braiding it.
Ron: Your hands. He loves to hold them in is, and how perfectly your hands fit together.
Draco: Your smile. With all of his family struggles, the only thing that can brighten his day is your smile.
Fred: Your eyes. Fred will often get lost in your eyes. His favorite part of the day is when he gets to see you and your gorgeous eyes.
George: Your laugh. Luckily, George is a funny guy, so he often gets to hear your laugh. No matter how long you guys are together he can't help but smile every time he hears your laugh.
Neville: Your nose. Whenever he sees you after a long time of being a part, the first thing he does is kiss your nose. He loves to see the smile you make when he does it.
Cedric: Your (face) cheeks. Cedric loves to kiss your cheeks. He thinks it is so cute when you blush and your cheeks turn bright pink.