How can a girl impress her boyfriend?

Wear jeans/knee length or longer skirt with a top that looks pretty but doesn't expose your boobs and isn't backless, don't wear too much make up (clear lipgloss is good.) Smile and suck up to both parents but don't be sugary. Don't act like the perfect girlfriend as it is in your boyfriend's eyes, act like 'a respectable young lady' and don't be a snob. And eat all the food on your plate, no matter how many courses there are. This may mean skipping whichever meal comes before, but don't tell them you did or they'll start thinking "ANOREXIC!!!". Hope this is useful.