Make sure you don't have bad breath! try not to talk too much during the movie, or you will sound desperate, and also, try to make contact with his/her hands a lot, and maybe share a snack or soda or...
Wear something that he will love to see you in. Wear natural colored makeup. Maybe skinny jeans or flare jeans with an off the shoulder with look cute. Bring a light jacket if you get cold.