Then you wait (while simultaneously moving on with your own life), and hope she has some combination of A) coming to her senses, and B) being re-attracted to what attracted her to you to begin with.
People tend to value most that which is difficult to obtain.
Starsky
So back to detaching. That's the key?
Not to detach just to win her affections back ... you would be defeating the purpose of cutting the string and constantly picking it up to see if there is a nibble right? We call this Temp Checking
You have to turn focus off them, focus on you and what you can do to become a better person ... for YOU .. not them.