2 Answers

Find a way to accept she does not love you and seek someone who can love you. You are not alone with this. Many people finding themselves falling in love with a person who does not fall in love with them back. It's as simple as this, she is not the one for you or she is just not ready to love someone like you. It's hard but you will get through this. You will find the right one in time. 

If you and she don't know each other very well, keep on being nice to her and making general converstation with you and as time goes by, she might notice your attributes and get more interested in you . And something might blossom. In the meantime, she will appreciate you always being there for her, but don't let her walk on you.