Hey! Playing the game I've found that you actually get traits like cute going to the book store and talking with the shop assistant (the grey haired dude) so that you can buy a specific book and it tells you the trait it will give you. Then you need to read said book by clicking the shelf in the room at night time and you'll get the trait. Otherwise you can also get traits by eating at the restaurant by talking to the lady (this gives you traits like energetic, ramen lover, etc.) !!