How can one impress a girl?

1) Dress to impress: your physical appearance is important. The way you dress is the way you will be addressed. Wear something that suits you, pick a color that looks good on you. Make sure your clothes are clean, you have a clean hair, good shoe to go and smell good too.

2) Be well mannered: say "please" and "thank you" when necessary, open the door for her, listen to her when she speaks. A good manner will leave a good impression but a bad impression will push her further away from you.

3) Study her for some time: get to know the kind of person she is, what she likes, send her a gift, bring her a beautiful bouquet of flowers or get her a book by her favorite authors. Help her solve a problem, make her feel special and make her laugh as often as you can.