Rule #1: Stop trying to have a relationship with someone who does not want one with you!
Today we call that being a "stalker" or a "fatal attraction".
The old days of sending flowers, leaving romantic notes/poems, and showing up wherever you think she may be are no longer considered "courting or a romantic pursuit". Most people call it SCARY! Sexual Harassment isn't something you want to be known for.
The best approach is to tell someone you find them attractive and would like to get to know them better. Follow that by asking if they would like to get together to go out......etc
Based upon their response you will know if the interest is mutual. Always keep in mind there are more than 6 billion people on this planet and the odds are in your favor that more than one is attracted to you and would like to get to know you better. If she is not one of them then move on!