Whats are some things i should look for to find out is a girl is interested in me?

i started hanging out with a girl thats been single for about a month now and i asked her to dinner and a movie last week. she said yes but we ended up eating then walkin on the beach instead of the movie which was fine. i couldnt exactly tell if she thought it was a date or not. as much as i wanted it to be i found out from a friend that she didnt think it was. im not sure what i am suppost to do from here. a